He Blinded Me With Science
by Ittlebitz
Summary: Derek Hale was a successful detective in New York, but he felt a pull back to Beacon Hills, his boyhood home. When he returned home and joined BHPD's Department of the Supernatural, he meets Dr. Stiles Stilinski, the brilliant but outrageously flirtatious Head of Forensics. Stiles gets under Derek's skin immediately with his blatant behavior, yet reminds him of a secret love.


I have been struggling with a bit of writer's block on looking for it (finding heaven), so I decided to write something to help me over the hump. The plot bunny for a Sterek fic based on a manga I once read started humping my brain, so I decided to give it a go. Before I knew it, I had this monster one shot. All I know about police departments and forensics comes from the movies and Forensic Files, so any inaccuracies are my own.

Many thanks to Beth for her beta skills, and to Sam for the read over and help with that one tricky spot in the fic. I couldn't have done it without you both. I also deeply appreciate Athena for her encouragement, the occasional kick in the butt I needed, and the promise of porn as a reward for finishing. Look, I wrote a thing!

There are some elements of this fic that may cause some discomfort for some readers. _**spoilers** Stiles is very aggressive and inappropriate with his flirtations with Derek, making him feel uncomfortable and angry. He easily crosses the line into sexual harassment at times, something that is generally laughed off by everyone. At one point he handcuffs Derek to a table in order to get a print from him, rather than just asking, and kisses him while he's cuffed. He also blows him in the gym shower without getting consent first. He does acknowledge his behavior and apologize once he and Derek start growing closer. Ennis threatens Stiles with rape and mentions having raped before. There is also minor character death (Heather). **end spoilers**_ This fic is based on the manga I.D. and borrows its basic plot and some of its dialogue from it. I can be reached on my tumblr as well! **ittlebitz . tumblr . com** Feel free to drop me a line or flail over Sterek with me!

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><p>Detective Derek Hale checked his reflection in the rear view mirror of his car, carefully checking to make sure not a hair was out of place. He bared his teeth, taking care there wasn't anything caught in them, and took a deep breath before getting out of the car.<p>

It seemed rather silly, to be so nervous. He had been a successful and elite detective in New York City, for crying out loud! Surely he could handle a smaller city like Beacon Hills, although he had to admit, Beacon Hills had changed quite a bit since he had left it behind as a teenager. The rather boring, sleepy little town he remembered had given way to a bustling city that was home to the state's largest Department of the Supernatural.

While there was never a dull moment in New York, lately Derek had been feeling a pull to return home. His sister and pack mate, Cora, had encouraged him to do what was best for himself. She was the assistant district attorney and loved the excitement of New York, but she had always known Derek hadn't settled in quite as much as she had when the tragedy that killed their family drove them to the other side of the country. She pushed him to contact Alan Deaton, an old family friend who was chief deputy in Beacon Hills, to enquire about any availability on the police force back home. He had emailed Deaton with no real expectation other than to placate Cora, but then he received a warm reply in return that mentioned a recent opening for a detective. Apparently one of the force had recently gotten pregnant with twins and had been advised to scale back on the job.

Derek had kept quiet about the email for a week, thinking over pros and cons about accepting the transfer. Finally, he went to Cora to talk to her and see what she thought. She had hugged him tightly and cried a little as she told him to pack up and go home, that she would miss him but he had to follow and make his own destiny. He had gone home and emailed Deaton immediately, including a résumé, and in two days got a call from him, telling him he was hired and how soon could he begin. He also extended a welcome from the current territory Alpha, welcoming his return. Within a week he and Cora had his small apartment packed and ready to be shipped across the country.

Back to Beacon Hills.

Which brought him to today. He had rented a loft apartment in a charming old section of town and had spent the weekend unpacking and organizing. Although the town was still familiar in a sense, Derek was amazed at how different it had become since he had last seen it. He had yet to go to the grounds where his childhood home had once stood. He wasn't sure he was quite ready for that yet. But enough ruminating; he had a job to get to. Straightening his shoulders, Derek strode to the door of the precinct office, taking a quick moment to adjust his tie. Opening the door, he walked in with what he hoped was confident authority. The lobby was empty, with the exception of a blonde woman behind the desk with her back to him.

Derek cleared his throat to make himself known. "Excuse me," he said.

The woman turned around, her look of surprise quickly giving way to a saucy smirk. "Well, well, who have we here? Hottie Hale, in the flesh! And don't tell me, you're the one they've hired to replace me! That's awesome! Stiles is gonna flip!" she crowed, raking her approving gaze up and down his form.

Derek was taken aback slightly. He couldn't remember this woman, though she clearly remembered him. Without a doubt, she was a werewolf, and Derek knew that she hadn't been part of his pack before. "I'm sorry, ma'am, I don't believe I've had the pleasure—"

"No problem, I was still in middle school when you were a hotshot basketball player and I doubt you'd remember me. Besides, I was still human back then," the woman said cheerfully. She held out a hand with a grin, her eyes flashing gold. "Officer Erica Reyes-Boyd. Member of McCall pack and former detective." She rubbed her belly that showed a gentle roundness and Derek remembered Deaton saying a pregnant detective had stepped down.

He shook her hand and smiled back at her, flashing his own red eyes. "Derek Hale. Hale pack Alpha, returning to Beacon Hills. I don't know whether to congratulate you or thank you, since you're what got me the job."

Erica laughed. "Such a smooth talker! Your reputation precedes you, though. Never mind the Chief practically doing a happy dance when he read your résumé. He might have moved me to desk duty just on principle." She handed him a packet of paperwork with a chipper smile. "Here's what you have to fill out for HR, your background check and drug tests have already been processed. You don't have to do it now, but you want to complete that and get it in sooner rather than later because Tara will skin you, big bad wolf or not. You're going to be working with Detectives McCall and Lahey in the Paranormal Division. They're expecting you, so if you'll go down the hallway, second door on your right, you'll find them. They'll show you your desk and give you the tour! Welcome home!" Erica beamed at him.

Derek smiled warily in return. He felt slightly dazed and was willing to bet Erica had been a force to be reckoned with in the interrogation room. He walked to the area she had indicated and knocked on the door before entering. Two men were in the office, one darkly handsome, the other, fair with cherubic features. They looked up as Derek walked in.

"Detective Derek Hale, reporting for duty," Derek said by way of introduction, cringing slightly at how stiff he sounded.

The dark haired man gave him a friendly grin and held out a hand. "Derek! Good to meet you, man! Scott McCall, detective and territory Alpha," he said, flashing red eyes. "Welcome home."

Derek nodded respectfully, flashing his own red eyes and feeling a mix of emotions standing before the werewolf who was currently in charge of what had been his family's territory for years. He was glad that Scott seemed more interested in him as a detective and partner, rather than viewing him as a possible threat and trying to make him submit.

"This is Detective Isaac Lahey," Scott said, gesturing to his partner.

Isaac lifted a hand in a wave. "Nice meeting you," he said with a flash of gold eyes.

Derek nodded again, having recognized the scent of another wolf. So much had changed since he left Beacon Hills. He gave them his best confident grin and said, "I look forward to working with you both."

Isaac smiled easily. "Come on, let us show you around."

The two detectives showed Derek around the office. He had a desk of his own in the same room as Scott and Isaac, and Scott told him business cards were already on order for him and due in within the next day or two. They escorted him to the break room, showing him where the refrigerator, coffee maker, and water cooler were. They waited while Derek got his security badge made, and when he rejoined them, Scott handed him his parking pass with a flourish, along with his engraved official badge.

"We accept him, one of us," Scott and Isaac chanted merrily as they returned to their shared office space.

Derek laughed, feeling more at ease. "Gooble, gobble," he retorted, feeling ridiculously pleased to understand the reference.

Isaac's eyes lit up with amusement and he clapped Derek on the back. "Okay, newbie, I've already emailed you the details of this latest case were working on. There's an icon for the email system on your desktop. Once you click it, you'll be walked through finalizing your setup and you'll be good to go." He grinned when Derek thanked him and went to sit at his own desk.

Working was cathartic. Derek always let himself get immersed in a case. He loved looking at all the puzzle pieces and determining how to make them fit. Time flew by as he read over the case and before he realized it, half of the morning had flown by. He stretched and was contemplating getting a cup of coffee when he heard a cell phone ring with a Hungry Like The Wolf ringtone.

"Damn it, Stiles, when did you even get my phone to change the ring tone?" Scott grumbled as he fished his cell out of his pocket. "You're an asshole," he answered without preamble.

"Tsk, tsk, that's no way to greet your best friend that you want to do you a favor." Derek couldn't help but overhear the cheery voice on the other end. "What is it this time?"

"Just a standard run and check," Scott answered, looking sheepish as he placed a hand on the back of his neck. "It's for one of Kira's friends."

"Dude," groaned the voice on the other end, "she said yes. You're already dating. You don't have to keep trying to win her over!"

"I know, I know," Scott agreed, sounding chagrined. "But she's the first girl I've really liked since Allison and I broke up, you know that. I just wanna make her happy."

"Ugh, fine," the voice grumbled. "But you owe me one, you pain in the ass. And if I go down, don't for a moment think I won't take you with me!"

Scott beamed happily. "Never gonna happen, dude. You're too stealth to get caught."

"Flattery will get you everywhere. Now get the sample to me so I can get to work on it. If I get it done by 2:00 I can send it out today," replied the voice.

"You're awesome, man. I owe you," Scott grinned.

"Yeah, yeah, now hurry up and get it to me so I can process it and get it ready. Later," the voice said, and the call ended. Scott shook his head with a fond look as he pocketed his phone.

Derek stood and stretched, grunting softly as a pop sounded in his lower back. When Scott cleared his throat, Derek turned to look at him warily.

"Sooooo, newbie. I need a favor," Scott said, his face bright and suspiciously innocent. He reached into his desk and took out a sealed evidence bag. "You need to learn where things are. I need you to take this to the forensics lab for DNA testing. Make sure you give it only to Dr. Stiles Stilinski."

Derek blinked twice. "Stiles? His name is _Stiles?_" he asked in confusion as he took the bag from Scott.

Isaac snickered. "Just trust us, it's easier."

Derek looked between them, feeling unsure. Even though he was an experienced detective, as the newest member of the team he expected to be treated somewhat like a rookie until he proved himself; it wouldn't be the first time he'd been the gofer or the one to do coffee runs. But there was something about the mischievous grins the two detectives were giving him that gave him pause. He looked at the evidence bag he held.

"This is something from a crime scene, then?" he asked slowly.

"Something like that," Scott reassured him as he gently pushed him towards the door. "Go forth! And learn well!"

In his confusion, Derek missed hearing Isaac remark, "Stiles is going to eat him alive."

Derek made his way towards the far end of the building, where he remembered seeing the forensics department during his whirlwind tour with Scott and Isaac earlier. The door to the lab was slightly open and he could hear rock music playing inside. He shook his head in disapproval. Back in New York, the forensics department had been run with military precision, and the department head would have sooner stripped down to her underwear and pranced around the lab singing "Everything Is Beautiful" before she would have allowed rock music to be played there. Squaring his shoulders with a sigh, Derek knocked on the door.

"Hello? Dr. Stilinski?" Derek called as he pushed the door open. He was shocked to see a young man with wildly ruffled dark hair sitting behind the desk with his feet up on it, playing something on his phone. He wore dark rimmed glasses and had on a flannel shirt as well as a Captain America t-shirt under his rumpled lab coat, and the feet on the desk were clad in battered Chuck Taylors. He had a sucker in his mouth, and Derek tried not to notice that the lips pursed enticingly around the stick were a perfect shade of pink and shaped like they were made for sin.

The man looked up and grinned at him. "Hey! A new face! You must've just started. The new detective, right? No way I would forget someone who looked like that." He finally paused for a moment, studying Derek's form in a way that made him feel even more discomfited.

Who was this guy, anyway? Dressed so casually in the lab, behaving in such a thoroughly unprofessional manner. Derek had half a mind to turn him in to Dr. Stilinski once he met him to give him this sample. His outrage grew when the guy tilted his head to one side and asked, "Aren't you too hot to be a detective?" all while twirling his sucker between long, slender fingers.

"Detective Derek Hale, Paranormal Division," Derek ground out. He couldn't believe this guy actually worked in the lab. "I need to see Dr. Stiles Stilinski, I have something to give him from Detective McCall."

"At your service. I'm Stiles Stilinski," stated the guy, popping the sucker back in his mouth and holding his hand out to Derek, who was too stunned to do anything other than stare at him. _This _was Dr. Stilinski?

Stiles' grin faded when Derek didn't take his hand. He stepped back and said, "Sorry, I've been sleeping in the lab for the last few days while working on a tough case. Do I smell?" he asked, sniffing his sleeve lightly. "You're a werewolf, right? I try not to offend the finer sensibilities of my wolfies."

Derek glanced around, wondering if there were hidden cameras and Ashton Kutcher would be jumping out at him any moment yelling that he'd been Punk'd. Scrambling to regain his mental facilities, he held out the bag he held. "Ummm. Here. Detective McCall asked me to deliver this for DNA testing."

"Sure thing," Stiles replied easily, taking the bag from him. "That'll be twenty bucks."

Derek felt his jaw drop open. "_What?_"

"My ID fee," Stiles smirked.

Derek couldn't believe what he was hearing. "You're _charging_ me for this?"

"Well, I _am _doing this as a favor and on the side," Stiles pointed out as he shrugged nonchalantly. He broke open the seal and looked inside. "Let's see what we have. Ah! Definitely helping out a lady."

"What is it?" Derek asked, feeling curious in spite of himself.

"A condom," Stiles replied blithely. "'The baby isn't mine,' or so says the loser she's sleeping with." He stood up and walked around the desk to sit on the edge in front of Derek.

Derek resisted the urge to wipe his hand on his pants. Damn McCall anyway, he'd put salt in his coffee instead of sugar when the time came. "Is it appropriate for you to be doing this sort of thing at work?" he demanded as Stiles leaned back to open one of his desk drawers. He took out another sucker and began to unwrap it.

"Of course not. Which is why this is going to be our little secret," replied Stiles cheerfully.

"You've got to be kidding m—" Derek's outraged reply was cut off when Stiles shoved the sucker in his mouth. He sat stunned for a moment, stick poking between his lips, the taste of sugar and cherries coming quick on his tongue. Finally, his senses returned and he pulled the lollipop out of his mouth.

"Why did you give me a sucker?" he asked belatedly.

"To make sure you stay quiet about this," Stiles said delightedly, giving Derek a wink. "Sweets to the sweet!"

"I can't believe you're eating in the lab!" Derek blustered, feeling horribly off kilter. He wasn't accustomed to such behavior from a lab worker, much less the head of the lab itself!

"Oh, come on, don't be such a sourwolf!" pouted Stiles. He held out an evidence bag. "Here. If you don't like it, put it in here."

Derek stuffed the sucker in the bag. "I've delivered Detective McCall's sample, so if you'll excuse me, I have work to do!" He turned on his heel and strode for the door.

"Detective Hale!" Stiles called sharply, causing Derek to pause at the door to look back at him in surprise. "Did you know there are two types of DNA identifications?"

Despite his misgivings, Derek couldn't help feeling intrigued. His mother had always told him knowledge was power. And Scott had told him to learn. Maybe this was what he meant. "What are they?"

Stiles held up a hand, sliding effortlessly into lecture mode. "First we have nuclear DNA, which we use in testing fresh evidence, and then we have mitochondrial DNA, which can be used in identifying human remains."

"How are they different?" asked Derek, his interest piqued.

"Still gonna report me?" teased Stiles with a waggle of his eyebrows.

Derek felt his scowl return. "Are you suggesting we're trading favors now?"

"Cool, huh?" Stiles answered with a broad grin. "You're obviously very dedicated to your job. And you seem to have an interest in mine, which is awesome."

Before Derek could retort, Stiles continued on, back in lecture mode. "When identifying with nuclear DNA, both sets of parental genes are arranged so that each sequence is unique. Mitochondrial DNA doesn't mutate during recombination, which can make it a powerful tool for tracking ancestry. The thing is, it doesn't identify the father. When a sperm fertilizes an egg, the tail doesn't enter the egg. The tail is where most of the mitochondria are located," he explained."So a fertilized egg contains a mixture of the father and mother's nuclear DNA, an exact copy of the mothers mitochondrial DNA, and none of the father's mitochondrial DNA. Therefore, children only inherit their mother's mitochondria. When dealing with sex crimes, often evidence is left behind, and this is one way we use to identify the offender."

"Wow," Derek said, feeling impressed in spite of himself.

"Amazing, right?" asked Stiles enthusiastically. He held up one long finger. "However, in some cases there may not be biological evidence, or there may even be semen with no sperm in it. Your job is to make sure the perp doesn't get away with it."

Derek was just about to remind Stiles that sex crimes were rarely an issue in the Paranormal Division when the quirky doctor caught him off guard again.

"Shall we begin conducting your training in collecting samples?" Stiles asked.

"I'm sorry, w-what?" stammered Derek. That hadn't been mentioned at all.

"We can extract your DNA right now for the record!" Stiles crowed, reaching over and grabbing a plastic vial from the counter. "Here you go! Your fresh semen, if you please!"

"Excuse me?" demanded Derek, feeling more outraged by the second.

"Oh, come on. You know how," Stiles said with a dismissive wave of his hand. "You can even do it right here, I don't mind. I'd be more than happy to lend you a hand, if you like!"

Derek couldn't believe what he was hearing. "This is sexual harassment!" he spluttered.

"No, no, Derek, this is work," Stiles reassured him with a saucy grin. "Not like you've never let anyone touch you before, right?"

"It's _Detective Hale_," Derek snapped. Stiles had moved to stand before him and he couldn't help but notice the eyes behind the glasses were a warm brown, the skin lightly sprinkled with moles, just like _hers. _He quickly stepped back, shaking his head. "I've done what I was asked to do. I have to get back to work." He grabbed the container from Stiles, turned, and nearly fled the room, cringing when he heard Stiles call out behind him:

"I'm looking forward to working with you, Derek Hale!"

When the door slammed behind Derek, Stiles grinned to himself and held up the evidence bag with the sucker in it. "Jackpot! Today's winnings, a sample of the hot newbie! Time to get to work!"

Derek stepped into the restroom and turned the water on to wash his face. He wasn't used to being so caught off guard by anyone, much less a smooth talking forensics professional. Normally he was fully in control of himself and the situation he was in. So why had it been so different with Dr. Stiles Stilinski?

His traitorous mind brought back Stiles' face in vivid detail, complete with perfect mouth, brown eyes, and a smattering of moles. Derek cursed softly. He obviously had a type. He had never truly gotten over Paige, her death when they were teenagers marking him for life. One of the things that had drawn him to Jennifer Blake when they were in police academy together was her similarities to Paige. If he concentrated hard enough, he could almost believe she was the grown up version of his long lost first love. He had never acted on his infatuation, instead adoring her quietly from afar. But he had sworn that he would become a high ranked Detective in order to impress her, and that one day he would find her and profess his feelings.

Sure. That's all it was. He had been thrown off by Stiles and his similar traits. Feeling better about coming to a reasonable conclusion, Derek readjusted his tie and headed back to his desk. He had been gone quite some time, thanks to Stiles and his shenanigans, so he stopped by the lounge first and poured three cups of coffee to take back with him. He put them in a tray to carry, along with plenty of sweeteners and cream, and went back to the office.

"I'm back," Derek announced as he pushed the door open with one hip, carrying his offering before him.

Isaac's eyes lit up at the sight of coffee. "You are a godsend," he said, wrapping his hands reverently around one of the cups before adding several packs of sugar and creamer to it.

"So what did he say?" asked Scott with an easy grin.

"Who? Dr. Stilinski?" Derek hedged.

"Yup," drawled Scott, his mouth making a pop on the p sound. "Stiles is something else, isn't he?"

"He's something else, alright," retorted Derek dryly. "Although what exactly, I'm sure I have no idea. I did learn a few things, though, about DNA testing and sperm."

"Oh, that!" laughed Scott. "I'm helping out a friend of my girlfriend. Hair or saliva would do the trick as well, but if she tries to take hair or shoves a q-tip in his mouth, dude's likely to get suspicious. So getting his sperm instead is the logical choice."

Derek felt himself go deadly calm. "Hair or saliva will do as well?"

"Sure! Didn't Stiles tell you? He gave you a sucker, right?" asked Scott.

"Er, yes," Derek said.

"And he kept the stick, didn't he?" Scott guessed, chuckling when Derek's scowl grew darker. "He probably has every employee in BHPD on file."

Derek fumed silently as he remembered Stiles giving him an empty evidence bag to place his sucker in. That had been all Stiles needed, but he actually had the balls to ask Derek to provide him with a sperm sample, offering to jerk him off, even! And to top it all off, he had in a way reminded Derek of Paige and Jennifer. He wasn't sure if he felt more anger or humiliation at that moment.

"Yo, Scotty!" came a cheerful voice from behind him.

Derek whipped around to see Stiles standing in the doorway, a broad smile on his face. "And if it isn't _Detective Hale, _as well," he drawled, lips pursed obscenely around yet another sucker.

"Stiles! Listen, man, thanks for doing me that solid. Kira's really stoked that you could help," Scott said with a happy grin.

"I'm sure she is," Stiles smirked. "And once again, you reap the benefits of all my hard work."

"Excuse me, but could I talk to you a second?" Derek interrupted, grabbing Stiles by the arm and practically dragging him into the hallway, leaving behind a rather perplexed Scott.

Fortunately the hallway was deserted. Derek shoved Stiles against the wall and got up in his face. "Why did you lie to me?" he ground out, seething in anger.

"Lie to you about what?" asked Stiles, looking confused.

"About needing a sperm sample from me, when you already had my saliva on that damn sucker!" Derek said in a harsh whisper.

"Oh!" Stiles said, an easy grin crossing his face. "That wasn't a lie. One day, detective, you may actually need to collect that from a suspect."

"Highly unlikely, considering I work in _Paranormal!" _Derek growled, letting his eyes flash red.

"But if the occasion ever arises, so to speak, you know what you're looking for," Stiles said easily, ducking out from under Derek's grasp with an ease that surprised him. Stiles straightened his lab coat and shifted the sucker from one side of his mouth to the other. Derek hated himself for watching the movement with almost rapt fascination.

"Okay, so good luck on the job, Detective Hale," Stiles said, turning to walk back towards the lab. "And don't forget about my ID fee!" he tossed over his shoulder.

Derek stood stock still in the hallway, watching Stiles' retreating back. If he had it his way, their paths wouldn't cross very often, if ever.

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><p>After several weeks, Derek fell into an easy routine. Working with Scott McCall was easier than he had originally thought it would be, and together with Isaac Lahey, they were a force to be reckoned with. Derek worked hard during the day and kept himself busy at night, working out, studying case files, and occasionally Skyping Cora, who was far more interested in his lack of a love life than his satisfactory professional life, much to Derek's consternation.<p>

Happily, he had not come into contact with Stiles since that first meeting, though Derek thought about it far more often than he cared to admit. The specimen container Stiles had given him was sitting on a shelf in his bathroom, and for some reason he couldn't fathom, Derek was loathe to throw it out. It was a waste of work materials; that was probably it. Maybe he could sneak it back to the lab without running into Stiles again.

All was going smoothly until one night towards the end of their shift, Scott turned to Derek with another of those blasted specimen bags.

"I have a bit more to do before I can head out. Would you mind dropping this off to Stiles on your way?" Scott asked with a winsome smile.

"_Again?_" Derek asked in exasperation. "Honestly, Scott, does your girlfriend not have any drama-free friends?" He shook his head. "Besides, Dr. Stilinski and I are hardly what you'd call friends. We don't exactly get along."

"How can anyone not get along with Stiles?" asked Scott, sounding confused by the very notion. "C'mon, please, Derek? I just have a couple more things to finish on the paperwork, then I can get going to Kira's place. It'll only take you a minute," he cajoled.

Derek rolled his eyes and sighed heavily, hoping he sounded just as put out as he felt. "Ugh. Okay, fine, but you so owe me."

Scott's grin lit up his face. "Dude, you're the best. I knew I could count on you! And give Stiles a chance. He comes on strong at times, but once you get to know him, you'll really like him!"

Derek's only response was to roll his eyes and huff in annoyance as he left the office. It wasn't so much that he didn't _like _Stiles, per se. It was more that he got under Derek's skin; and not necessarily in a good way, although it wasn't exactly a _bad _way either. Stiles left him feeling confused, something Derek was unaccustomed to. The fact that Stiles was enough to make him forget about Jennifer more often than not these days was just another strike against him as far as Derek was concerned. Darn Scott anyway, making him do this. Derek would be glad when his days of being the new addition and therefore, the errand boy, were over with.

Approaching the lab door with a slight sense of dread, Derek decided not to stand on formality. "Excuse me," he said loudly, announcing his presence as he shoved the door open.

To Derek's surprise, Stiles was nowhere in sight. His iPod was plugged into the speaker and music was playing, so obviously he hadn't left for the night. Derek shrugged to himself and decided he would just leave the specimen on Stiles' desk with a note and get out while the getting was good.

"Derek!" crowed a happy voice behind him.

Derek whirled around just in time for Stiles to snap a set of handcuffs on one wrist. He stared at it in disbelief. "What the hell are you doing?" he demanded furiously.

"It's no big deal," Stiles reassured, which did nothing to alleviate Derek's anger. "I just need your assistance with something."

"Then why the hell did you handcuff me?" shouted Derek.

"Duh! So you won't run away!" Stiles grinned, ever present lollipop bulging one cheek out slightly. Derek felt himself flushing slightly as he watched Stiles' tongue move in his mouth and felt his anger rise in response.

"Don't you dare try any of your funny business," he snapped irritably as Stiles manhandled him to a stool with surprising ease and snapped the other cuff in place so that Derek's arms were pinned behind him and looped around a steel table leg. He gave an experimental tug and was surprised not to feel any give.

"Wolfsbane infused," Stiles explained cheekily, causing Derek to flush harder at being caught. "Both the cuffs and the table. One can't be too careful when working amongst werewolves. Won't hurt you, but you can't use your strength to break them. Cool, huh?"

"What exactly is this all about?" Derek demanded, sure that if he would have a splitting headache right about now if he could get such a thing.

"I'm assisting in an investigation, and I need your full cooperation," Stiles answered distractedly, hunting around on his desk and making a triumphant sound when he found what he was looking for. He turned to Derek with a smile of pure glee and held up a red lipstick. "This won't hurt at all. I just need to put this on you!"

Derek stared at him incredulously. "What the hell kind of investigation are you doing, exactly?" he demanded.

"Shush, no talking," Stiles said as he moved in and began applying lipstick to Derek's lips. When Derek went to struggle, he scolded, "Do you want me to mess this up? Hold still, you big baby!"

Held there by the wolfsbane cuffs, at Stiles' mercy, and utterly confused, Derek gave in and held still while Stiles applied the shiny red gloss to his lips with a precise skill that was almost scary. When he was finished, Stiles stepped back to admire his handiwork.

"You look fantastic!" Stiles chirped cheerily. "My friend Ginger Snapp, drag queen extraordinaire, would be so proud of my mad lipstick skills. Hold on, such a moment has to be immortalized!" To Derek's further annoyance, Stiles took out his cellphone and snapped his picture. He pocketed his phone with a smugness that made Derek growl in response.

"Easy, Cujo, we're almost through," Stiles said as he got a square of plain white paper and pressed it to Derek's lips. "Don't move," he ordered. "If you smear the print, we have to start all over."

Derek willed himself to remain perfectly still, sure he was probably flaying Stiles alive with his eyes. Stiles was completely undeterred, however, and was rubbing his fingers lightly across Derek's lips. Derek could feel the heat of his touch even through the paper, something that only annoyed him further. After a moment where Derek was sure he was going to lose his mind altogether, Stiles finally stepped back and peeled the paper away from Derek's mouth with a flourish.

"Voila!" Stiles crowed delightedly. "A perfect kiss print!"

"Yay," gritted Derek from clenched teeth. "Now do you mind telling me what this is all about?" he snapped, jiggling his cuffed wrists.

"Did you know that lip creases are just like fingerprints?" asked Stiles.

Caught off guard, Derek paused. "They are?" he asked.

"You bet!" answered Stiles easily. "You know about fingerprints, of course. They are unique and don't change throughout a person's life. Finding fingerprints in an investigation can help lead to and identify a subject. You may see similar prints, but finding all fingerprints as a match can be rare. That's where you have your perp." Stiles held up a collection of lip prints and smiled. "And then you have lip prints. It isn't as commonly known, but a person's lips are equally unique and can also be used to ID someone."

Derek raised an eyebrow, trying not to look too impressed. "So, why did you take mine?"

"I'm trying to ID someone," Stiles explained easily. "One of the ladies in the office keeps getting anonymous love letters. There's no fingerprints, but each one was signed with a kiss. There's no post mark, so it seems the notes are being hand delivered to her desk when no one's around. I easily make the assumption that it's someone within the department, someone who is familiar with office security and when they can be undetected."

"So that's why you're doing this? You're taking everyone's lip prints to figure out who's behind it?" Derek asked. When Stiles winked at him and nodded, Derek once again rattled his wrists. "Well, now you have mine! Now, uncuff me right now!"

"Hmmmm, I dunno," Stiles said, sounding coy as he stepped closer. "I kind of like having Hottie Hale at my mercy." At Derek's surprised look, Stiles chuckled, the sound low and throaty. "You don't know what the women in the office call you? I think you can thank Erica for that one." Stiles studied Derek's face intently. "I recognized you, you know," he announced, taking Derek by surprise. "I knew who you were the first moment you walked into my office. I'm not surprised you don't remember me, though. I was just a geeky freshman back then."

To Derek's utter surprise, Stiles leaned down to him and captured his lips in a kiss. It started off gentle, at first, and then Stiles' mouth grew harder, pressing Derek's lips apart and sliding his tongue in to rub sinuously against Derek's. When Stiles finally leaned back, Derek stared at him in shock, lips tingling and slightly parted, panting slightly.

Stiles gave him a saucy wink and grinned. "Thanks for the kiss," he said, sounding completely unapologetic. "I haven't had one that good in a long time. Here, a token of my appreciation. Thanks for your cooperation." He popped a sucker in Derek's mouth and Derek closed his lips around the stick reflexively, still stunned by what just transpired. The sugary taste of grape filled his mouth as Stiles retrieved the keys to the handcuffs from his desk and finally released his wrists from their confines.

"Honestly," Derek mumbled around the sweet before taking it out of his mouth and gesturing at Stiles with it wildly. "What exactly were you thinking, kissing me like that?"

Stiles remained cooly unruffled by Derek's agitation. "I wanted to kiss you, so I did. You shouldn't ever let your guard down, Derek. Someone with lesser intentions could attack you."

"Lesser—" Derek sputtered, irritation making it hard for him to think. He had been affected by that kiss more than he wanted to admit, and seeing Stiles be so nonchalant about it only fueled his ire. No doubt he did things like this all the time! Finally Derek gave up and tossed his hands in the air. "Whatever! I'm going home!" he snapped in exasperation, turning and striding out of the office, making sure to slam the door behind him. Derek suddenly remembered the whole reason he had come to the lab in the first place and slammed a hand to his forehead in aggravation. Irritably, he opened the door again and shouted, "The evidence package on your desk is from Scott. And don't you dare even _think _about mentioning any ID fee!" He left again, slamming the door a second time.

Derek tossed and turned most of that night. Stiles had kissed him. And it had felt good. Amazing, even. Derek replayed the moment over and over in his mind, how Stiles' lips had fit just perfectly against his own, how soft they had felt. And later still, when he was stroking himself to orgasm, he fantasized how they would feel wrapped around his cock.

Needless to say, it had been a long, rather sleepless night.

The next day, Derek was sitting at his desk, staring unseeingly at an email that he had tried at least three times to read when he realized Scott had been calling his name.

"What? Sorry," Derek apologized, feeling embarrassed to have been caught drifting.

"'S okay," Scott replied with an easy grin. "Must be something fascinating to distract you like that."

Derek felt his face heating up when Isaac inadvertently saved him. "So, did you guys hear about Dahler in vice? Seems he had a bit of a crush on one of the girls at the desk and has been leaving her love notes. Wasn't man enough to sign them, just put a kiss on the outside."

"Is that what Stiles was making everyone kiss paper for?" laughed Scott.

"He may drive me crazy most of the time, and he could hardly be called conventional, even on a good day, but I have to admit, Stilinski gets results," Isaac said grudgingly. Then he brightened. "Guess it worked out for Dahler, though. She punched him in the face and then like an hour later people saw them making out in a corner of the cafeteria, so I suppose all's well that ends well."

"Wow. No accounting for taste, I guess," Scott said wonderingly, looking equal amounts fascinated and appalled. "Thank goodness I never eat there. "

"You got that right," chimed Stiles as he swept into the room. "You can chalk that one up to another case closed, courtesy of your friendly neighborhood Stiles."

Isaac scowled at him. "All you did was get a lot of people to kiss paper for you."

"Ah, ah, ah, Isaac! Don't underestimate my mental prowess! I'm much more than just a pretty face, you know," chided Stiles before he turned to Derek with a smile. "Your help was especially invaluable, Detective Hale." He held up his phone, which to Derek's horror had his lipsticked face set as the background. "Got it on my desktop, too. Gotta keep myself motivated, you know," he said with a wink. "So if you ever need anything, and I do mean _anything, _just let me know!" And with that he breezed out just as easily as he'd entered in the first place.

Derek sat frozen in place. He could feel the eyes of both Scott and Isaac on him and hoped against hope that a meteor would crash through the roof and land on him, or maybe the floor would open and swallow him whole.

"Well, on the bright side, that color really did suit you," said Isaac slowly. Both he and Scott collapsed into gales of laughter as Derek groaned and buried his head in his hands.

The next day, Scott and Isaac took Derek with them to the department's special work out center, designed especially for werewolves. Everything was reinforced and designed to withstand their strength, and Derek had especially looked forward to working out some frustration. He stood to the side dressed in BHPD sweats and t-shirt that clung damply to his muscles, drinking from a bottle of water while watching as Scott put Isaac through paces. Scott had already worked with Derek earlier, and he had been proud to stand his ground well against the other Alpha. Scott's look of respect had felt good.

"I see you're working hard," crooned a familiar voice, and Derek tensed as Stiles slid up next to him. "Work out clothes suit you, Derek. I may prefer them to your suit and tie!" He felt Stiles' approving gaze sweep over his form and grit his teeth.

"Yo, Stiles!" yelled Scott, trotting over to join them. He gave him a devious smirk. "You haven't shown yourself around here for a while. Fancy a quick round?"

Stiles returned Scott's grin with one of his own. "It's on like Donkey Kong, dude. Wouldn't want my skills to go rusty on me. Let me go change." And he strode towards the locker room.

Derek had listened raptly to this exchange between the two friends. He wondered how Stiles could possibly compete with any werewolf, much less Scott's Alpha strength. He noticed a crowd gathering around, a sense of anticipation in the air, and looked around in confusion. What was going on?

Scott stood out on the mat, jogging in place and rolling his neck. When the door to the locker room opened, a cheer went up from the assembled crowd and Derek stared in amazement.

Stiles stepped into the room dressed in the same sweats and t-shirt the rest of them wore, but the similarity ended there. It wasn't just that the sweats clung to Stiles' lithe form, or that the t-shirt fit tightly to muscles that Derek hadn't realized were hidden under the layers Stiles normally wore. His attention was drawn to the intricate tattoos that covered the exposed skin of his arms. Derek realized he had never seen Stiles without his many layers before. He recognized some of the designs, and everything clicked home.

A Spark. Jesus Christ, no wonder Stiles had been able to manhandle him into those cuffs. Now that Derek thought about it, he had never been able to smell Stiles before, either, which explained how he was constantly able to take him by surprise since a Spark could mask their scent much like an Alpha could.

Derek watched in fascination as Scott and Stiles moved around each other, sizing each other up. When Scott thrust forward, Stiles was easily able to counter the attack with one of his own. A wave of his hand, and Scott flew back a few feet.

"You call that giving it your all?" taunted Scott with a grin as he leapt back onto the mat. "Come on. You can do better than that."

Stiles smirked in return as they both circled each other again, each dipping and swooping, moving on attack and counterattack. Derek was amazed at how skilled Stiles truly was. It was like watching a dancer.

"Who would have thought such a flirty scientist could be so powerful," he mused aloud to no one in particular.

"Don't get fooled by that," chuckled a strangely familiar voice next to him.

Derek jerked in surprise and looked to see who had moved to stand beside him. A man in uniform and a stunning redhead in a lab coat stood watching the two competitors on the mat. The older man had brown hair and eyes with a familiar sparkle. Derek glanced at the stripes on the uniform the man wore, and realizing who it was, stood upright.

"Chief?" Derek nearly yelped, wondering if he should salute the department's highest ranking official while dressed in sweaty workout clothes. He had a flashback moment, remembering the chief, then a detective himself, being involved in the arson case that had killed Derek's family. He had been instrumental in bringing Kate to justice.

"Now, now, no need for formality. You're not on duty," the chief said easily. Derek could see his name badge with Stilinski engraved on it and looked towards the mat, his unspoken question obvious to the officer.

"My son," sighed the chief, an affectionately resigned smile on his face as he watched Scott and Stiles dueling on the mat. Derek nodded.

The redhead held out her hand. "Dr. Lydia Martin, State Head of Forensics," she introduced herself with a slight smile.

Derek took her hand and nodded respectfully. He had definitely heard of Dr. Martin. "Detective Derek Hale," he replied.

"Definitely don't let Stiles fool you," Lydia said, her voice knowing as she turned to watch Stiles again, her eyes fond, yet exasperated. "He's incredibly brilliant, could have been quite a catch. But he just isn't one to settle down, I'm afraid."

The chief chuckled and shook his head. Dr. Martin's words left Derek with more questions than answers. He noticed she called him Stiles, rather than Dr. Stilinski, which was unusual, and bespoke of more than a just professional relationship. She also didn't seem surprised by his Spark tattoos. He stared at them both silently as the chief took in a quick breath.

"Freeze, Stiles! You're under arrest for accessing classified data in the archives without authorization!" he barked.

Stiles swung around in shock. "Dad?" he asked just as Scott landed a sharp kick that sent him flying. The entire room, with the exception of Chief Stilinski and Dr. Martin, cringed.

"Ow, damn it," Stiles grumbled as an apologetic Scott helped him to his feet. He looked over to where his father stood and grinned. "Yo, daddio!" he said as he and Scott jogged across the mat to join them. "And Lyds, you're looking stunning as always. It's been a while."

Lydia raised a well groomed, unimpressed brow at him. "Right. And whose fault is that?"

Stiles placed a hand on the back of his head and grinned. "Well, you know, I've been busy."

Lydia unleashed her righteous fury on him. "How dare you?" she demanded. "Stiles, you _know_ better. Even the archive personnel know that they'd be punished for such a thing, and rightfully so. I've been quite lax with you because you're my top forensic pro, but damn it, there's a limit!" she scolded furiously.

"Oh, come on, I was just doing a quick peek to find something. It really was important, at least at the time," Stiles cajoled her, giving her a mournful puppy dog look. "Forgive me, oh loveliest of Lydias."

Derek saw that Dr. Martin was fighting a smile even as she remained stern. "You're just lucky I'm in a good mood today," she stated firmly, "so I'm willing to make a deal with you." She removed a plastic bag from her pocket and handed it to Stiles. "Take a look at this and I'll let it slide this once."

Stiles looked at the bag with interest. "A strand of hair? What kind of investigation are we talking here? Private? Like an affair? You know a pubic hair would be more ideal than this."

Lydia gave him a smirk. "Darling, when have I _ever _let you down?" she asked sweetly as she pulled another plastic bag from her pocket.

"Ah, you know me too well," Stiles said, smiling at her indulgently. "Why exactly did we break off our engagement again?"

Derek's eyes flew wide as he stared at Stiles and Lydia Martin. _Engaged?_

Scott leaned over to Derek and whispered, "They may not act much like it, but those two had quite the whirlwind romance going back in the day. Got engaged right out of college, and then three days before the wedding called the whole thing off!"

"Damn it, McCall, don't make me have you arrested," Lydia scowled at him. "You know that is the one failure in my life!"

"You definitely haven't changed," said Stiles, pretending to swoon. "Be still, my beating heart!"

"Just tell me what you figure out with those specimens," Lydia commanded, tossing her hair regally over one shoulder as she strode to the door to join the chief. She turned to level an intimidating stare on Stiles. "And no bullying that hot newbie, either," she said firmly. Head high, she strode out of the gym, the chuckling chief close behind her.

Scott laughed and clapped Stiles on the shoulder. "She still doesn't miss a beat, does she?"

Stiles grinned sheepishly. "Nope, not at all," he said, admiration clear in his voice.

"Alright, everyone, time to hit the showers!" yelled Scott with authority, flashing red eyes for good measure. The entire assembled group headed for the locker room, good natured joking and teasing among then all. Derek followed quietly, thinking about all he had just learned. He held back until everyone else was gone, showering alone while his mind raced furiously.

Stiles wasn't just a brilliant scientist. He was a Spark, one who had achieved the highest levels of magic. Even his old family friend Deaton, himself a former Druid, couldn't claim that much magic.

To top it all off, Stiles had been engaged to marry Lydia Martin, one of the most brilliant minds science had ever seen. She could have had her pick of fields and had opted for forensics, and within just a few years headed up one of the largest and most successful lab groups in the world. Truthfully, they made quite a stunning couple. With their combined brilliance they could have quite literally ruled the world of forensic science. Yet suddenly they broke things off, just before the wedding.

Derek had to admit, he'd never seen Stiles be so—gentle or intimate with anyone else. His eyes, when they looked at her, had held a tender expression Derek hadn't seen on him before. He wasn't exactly sure why it seemed to bother him, why his heart felt like it had sunk down since Stiles had realized Lydia was in the room. He shook his head and cursed himself for being so foolish.

"Obviously he's still in love with her," Derek scolded himself out loud, glad no one was around to hear him talking to himself. Maybe saying it out loud would make it more convincing.

"I'll always love her," said a voice behind him, " but I'm not _in _love with her."

Derek whirled around with an embarrassing squawk, despairing anew at the Spark ability that allowed Stiles to sneak up on him at his most vulnerable moments.

"What are you doing here?" Derek sputtered crossly, spitting out water and feeling horribly embarrassed to be overheard ruminating about Stiles' relationship with Lydia.

"Don't mind me," Stiles said cheerfully. His hair was wet and sticking up in messy spikes that still managed to look attractive, damn it. He was wearing nothing but a white towel wrapped around his waist, and Derek could see that his chest and shoulders were both toned and covered with more tattoos that seemed to reach around to his back as well. This just irked Derek more.

"I do mind," he snapped, feeling incredibly conscious of his own nudity and trying to cover himself without drawing Stiles' attention. "Very much so."

"You want to know, though, don't you," Stiles said seriously. "About Lydia and me." Water beaded on his lashes causing them to spike and look even more outrageously long. More drops of water clung to his bare shoulders, and Derek couldn't help but watch in rapt fascination as one trickled its way slowly down Stiles' torso to disappear at the terry cloth wrapped around his lean waist. He felt his cock twitch in interest and felt embarrassed all over again.

"It's none of my business," Derek muttered, wondering if it was possible to drown himself under the shower. The tile was cold against his back, and with a start he wondered how Stiles had managed to get so close to him without him realizing it.

"I love Lydia because she's so much like me," Stiles said, his voice still serious. "She's my best friend in the world and probably knows more about me than anyone, Scott included. Fortunately for us, we realized before it was too late that we just aren't _attracted _to each other. Quite a pity, actually. We were the absolute worst lovers to each other, to be honest, although we gave it our best shot. A marriage between us would have been a complete disaster. But I will always respect her for the brilliant mind she is, and as my boss. And I will always love her as my dear friend. That will never change, so long as I live."

Derek nodded briefly, understanding quite clearly. _Stiles would always love her. _

"On the other hand," Stiles said, his tone becoming more animated, "I happen to find _you _extremely attractive, Derek Hale. Truthfully, I'm at a bit of a loss as to exactly what to do with you. It's been quite some time since I've been this attracted to a man." To Derek's stunned consternation, Stiles dropped to his knees in front of him, ignoring the water that still pelted them from the shower head and soaked his towel.

"What are you doing?" Derek choked out, his entire body jerking as Stiles took his half hard cock in his hand, seeming to heft it curiously before studying it.

"Hmmm. Nice shape and color, good size, uncircumcised," Stiles muttered to himself.

Derek was sure he was going crazy. There was no way in real life that he could possibly be standing naked in a police gym shower while a forensics expert clinically described his dick. Unfortunately, said dick didn't get the message, growing harder in Stiles' explorative grasp.

"Ah, there we go. You're feeling it now!" Stiles said smugly, looking up at Derek in satisfaction and giving his cock a gentle squeeze, eliciting a short gasp from him. He licked his lips and Derek helplessly watched the movement of his tongue over that unfairly attractive mouth.

Derek was going to die of sheer embarrassment, he just knew it. If he survived this, he was turning in his notice the next day, moving to Canada, and changing his name. He would bet moose herding was peaceful, and probably didn't have dangerously attractive scientists with wicked mouths involved. "It's just reflex," he argued, wishing he sounded more certain. "Of course I'll be like that if you're touching me!"

"Really. But is it a touch thing, or a me thing?" Stiles said, sounding interested and looking enthralled by the sight of his fingers wrapped around Derek. "I'm pretty sure when I was with Lydia I was never this perky."

Derek opened his mouth to argue the use of the term "perky" when used in description of his cock just as Stiles leaned forward and licked a slow stripe up the entire length.

"_Guh,_" Derek said instead, feeling nearly lightheaded as most of the blood in his body apparently rushed straight to his groin at that very moment. An incredibly wet warmth that had nothing to do with the shower enveloped his cock and he could feel Stiles' tongue sliding up and down the shaft before pulling back to swirl around the head. His head hit the shower wall with an audible thud and he could feel his eyes rolling back in his head. His claws had popped out and they scrabbled wildly for purchase against the smooth tile, the scratching noise loud even under the rushing water. Derek couldn't stop the low, guttural moan that escaped from the back of his throat if he'd tried.

"Shhhhhh," whispered Stiles as he pulled his mouth off Derek and stood up. Derek could only whimper pathetically at the loss for a moment before Stiles pressed their mouths together, muffling the sounds he was seemingly incapable of stopping. He could taste the faint bitterness of himself on Stiles' tongue and shuddered. His hips thrust forward of their own volition, desperate for more contact.

In response, Derek felt Stiles take his cock in his hand again, the sinfully long and nimble fingers wrapping around him to stroke gently, gliding up and down easily over his wet skin. He felt a finger tease the tip, sliding under the foreskin to swirl around the head. Derek could feel the blood coursing hotly through his veins, could feel the pull of the wolf as he fought the shift. It struck him like a bolt of lightening that this was real, this was happening, and it was Stiles who held him, who was driving him to the brink of pure bliss, whose mouth had still not left his own. He felt the familiar tightening sensation in his balls building in intensity, and with a growl came in hard jerks over Stiles' hand.

Derek slumped in Stiles' arms, and he felt himself being eased back against the shower wall, aftershocks causing him to shudder. Stiles kissed him softly one more time before pulling away. He looked smugly pleased with himself, and Derek didn't have enough in him at the moment to work up any sort of self righteous irritation. His limbs felt like jelly and he was grateful he hadn't simply collapsed into a boneless heap on the shower floor. He and Stiles stared wordlessly at each other, and just as Derek was about to ask Stiles just what exactly had he been thinking to do such a thing, he heard voices approaching from the locker room. Giving Stiles a look that he hoped conveyed that they _would _be talking about this, Derek turned the water off and stepped out. He grabbed the towel he'd hung on the wall earlier and wrapped it tightly around his waist.

Drying off and dressing in what was possibly a record time, Derek stalked determinedly to the forensics lab. He paced restlessly, wondering irritably what was keeping Stiles. His mind was racing, trying to make sense of what had just happened. Just as he was about to give up and go in search of him, Stiles finally appeared. He was dressed in layers again, t-shirt and flannel under his lab coat, and if Derek hadn't seen his Spark tattoos earlier, he would never has suspected their existence.

"Are you okay?" Stiles asked cautiously, taking Derek by surprise. "I didn't intend to do that. I got carried away. Sorry."

Derek felt a pang of something that felt suspiciously like disappointment. Had Stiles been merely toying with him? "I'd agree you went too far," he said gruffly, not sure he understood exactly what Stiles was saying.

"But you did enjoy it, right?" Stiles asked, sounding hopeful. "I mean, you seemed okay with it, even though I'm a guy."

Derek opened his mouth and closed it again, thinking. While he had been waiting for Stiles he had tried to figure out his response to him. Wolves tended to be fluid with their sexualities; a beautiful person was a beautiful person. Yet Derek had never really found men all that appealing previously. Sure, he'd looked at guys before, but that was hardly unusual. And yeah, he and his college roommate had jerked each other off more than a few times, but so what, it had just been innocent fun, a means of getting off. Practically a rite of passage. Everyone did it. Didn't they?

Besides, he loved Jennifer. Didn't he? Derek hated how confused he suddenly felt.

Resisting the urge to rub his hand over his face, Derek sighed. This wasn't really the ideal time or place to deal with this anyway. "I'm fine," he said resolutely.

Stiles' grin lit up his face. "Awesome. So...how about a quick lesson about body hair?" Before Derek could respond, he continued on. "Hair is commonly thought to be an awesome source for DNA, but that isn't always the case. However, did you know that from a single strand of hair, we can still learn not only age and gender, but even clues about the lifestyle of its owner?"

Derek found himself intrigued. He'd always loved the classes where he'd learned the basics of forensics, and it seemed Stiles was determined that he develop an even higher understanding. Before, all he had done was gather the evidence and wait for the results. Now that he had a bit more knowledge about what went on behind the scenes, he honestly wanted to know even more.

"For example," Stiles continued, "this hair Lydia brought me. Look at it; it's long and red, right? If you look carefully, it's dyed. The color is even and reaches to the root, so this person has recently been to the salon. The end is trimmed straight, no splitting or discoloration. It likely belongs to a woman with the means to go to an expensive hairdresser, rather than coloring her own hair. Probably someone who takes pains with her appearance, always perfectly styled and well dressed when out and about."

Derek nodded. That made sense, and if he was working a case that would be a good clue in narrowing down a group of people.

"Other hair can be important, too," said Stiles, laying the plastic bag on his desk. "I remember a case when I was in school where a murderer was identified because he used a rug from his house to wrap the body before dumping it. There were hairs all over the rug, as well as the victim's clothes, that matched the killer's dog. That's one reason why you guys bring us even the smallest things you find on a case. It can be enough to blow it wide open. We narrow down and identify the bad guys so you can bring them to justice."

Derek was impressed. Of course he knew how important forensics were and how huge strides in the knowledge and technology had made solving cases much easier than in the past, even to the point that cold cases had been revisited and, in many cases, possibly solved. It was amazing to think that something like a blade of grass or a scrap of material could be crucial to a case.

"Now let's talk about pubic hair," Stiles said, eyes mischievous. "In the case of a person in their late teens or early twenties, the hair tends to be more fine, while someone in their late twenties and older, the hair is generally more thick and coarse. You can often tell if a person grooms down there and in most cases, how sexually active they are."

Derek wasn't sure if he liked the direction this conversation was headed.

"In your particular case, I can tell that you don't wax but you keep things neat and trimmed. For all that, you are either a virgin, or you haven't had sex in a long time. Either way, you aren't currently involved with a lover," Stiles stated conversationally, as though saying such things was perfectly normal at-work conversation.

"I cannot believe—how do you—damn it, this is sexual harassment!" shouted Derek, feeling his cheeks burn with a mixture of embarrassment and anger.

"But I'm right," Stiles remarked, looking unperturbed.

Enraged, Derek strode to the door. "I can't believe I fell for your whole educate-the-unwashed-masses bit again. I thought maybe I was wrong about you initially, but it's obvious you're an unprofessional asshole with absolutely no sense of boundaries!" The walls shook with the force of the door slamming shut behind him.

Stiles stood looking at the door in astonishment. "Well, damn," he muttered to himself, slumping into his desk chair. "Smooth, Stilinski. Way to manage pissing him off and undoing any positive strides you'd made. Maybe for your next scientific piece you could write an article named 'How To Lose A Guy In Ten Minutes Or Less.' Not that I actually had him to begin with."

* * *

><p>A few weeks later, Scott hungrily eyed the menu at Big Mama's Place, a popular diner in Beacon Hills frequented by its law enforcement officers. "Man, it's been too long since we've had the chance to just enjoy a pleasant, leisurely lunch. I'm starved! Everything looks so good, I want, like, two of everything."<p>

Derek studied the menu, pretending to be engrossed in making a selection and trying to ignore the odd atmosphere surrounding the assembled group.

Isaac, on the other hand, had no such compunction. "I don't know how it's possible for you to use pleasant as a word to describe any situation where _he _insists on tagging along!" he complained with a roll of his eyes.

"Who, me?" Stiles asked, dragging his gaze from Derek to scowl at Isaac. "C'mon, man, that's just rude. Scotty may be your partner, but he's _my_ brother from another mother. My hetero life mate, even!" He smirked as Isaac glared back at him. "I've been busting my balls working on this latest case, Lahey. Been eating and sleeping at the lab for days. If I eat one more heat 'em and eat 'em from the vending machine I'm gonna hurl. Besides, I love this place! Best curly fries in town!" He turned his head to sniff himself. "I don't smell or anything, do I? I cleaned myself up before coming here. What do you think?" he asked Isaac before raising his arm and yanking Isaac towards his armpit.

"Dudes, cut it out," Scott scolded as Isaac struggled out of Stiles' grasp and the two of them glared at each other. "Try to act like you've been in public before."

"He started it," pouted Stiles as Isaac straightened his tie and jacket.

"Whatever. You can be so revolting," Isaac snapped, moving so he sat further away from Stiles on the bench seat. Stiles stuck his tongue out at him childishly and Isaac responded with a flash of gold eyes and a warning growl.

Derek decided to try to diffuse the situation before it got further out of hand. "How can you possibly get any decent sleep at the lab?" he asked Stiles.

Stiles swung back to him with a sunny grin. "Awwww, are you worried about me, Detective? That makes it all worthwhile," he cooed, batting his eyelashes in a way that Derek found more distracting than he liked to admit.

Wondering why he bothered, Derek rolled his eyes and went back to his menu with a huff. He was rescued from having to respond by the dark haired waitress coming to take their orders.

"So, Stiles, Kira has this cute friend she wants to fix you up with," Scott said casually as the waitress left to put in their selections.

"Nope, not interested," said Stiles flatly.

"Aw, come on, dude! You could at least meet her, see what you think. You might be passing on the chance to meet the love of your life or something!" Scott protested. "You haven't dated anyone seriously or for very long since you and Lydia ended things. Are you wanting to get back together with her or something?"

Derek felt a weird twist in his gut at Scott's words. Stiles had told him he loved Lydia as a friend, but maybe there was more to it than that.

Stiles shook his head. "Never gonna happen, buddy. Our relationship is based solely on trust and friendship. No passion whatsoever, unless you count when we argue. It's hard to sleep with someone when you don't feel desire for them that way, you know?"

Derek listened, feeling a sinking sensation in his chest. Was Stiles trying to tell him indirectly he'd only been toying with him as a way to get off? Telling him not to make anything of what had happened between them? Derek wasn't even sure why that bothered him so much. It certainly wouldn't be the first time someone had used him for his body, after all.

"Besides," Stiles was saying, "I actually find Derek here far more attractive than any woman I've seen lately." He gave Derek an exaggerated wink across the table, and Derek rolled his eyes in response. It irritated him that he couldn't tell if Stiles was being truthful or teasing.

Isaac leaned across the table with a grin. "Derek, if you ever want to make a formal complaint of harassment to HR, I'll be a witness for you," he said.

"Like Tara would take anything you said about Stiles serious," Scott snickered. "She knows you guys too well."

The waitress returned to their table with a tray laden with food. "Here we go," she announced cheerfully. She began handing out plates, cautioning them about hot plates. Stiles popped a hot curly fry in his mouth and moaned in pleasure, causing Derek to choke slightly on his soda.

"Kali, you are a goddess among mortals," Stiles declared, grabbing the waitress' hand and pretending to swoon. "Marry me and let me take you away from this place. Then only I can enjoy your amazing cooking."

Kali laughed in reply. "But would I be the only one to enjoy your amazing flattery?" she teased in return.

"Ah, you got me there," sighed Stiles as he let her hand go and she walked away with a friendly wave. He was probably just naturally outrageously flirty with everyone, Derek decided. It was best he learn that now, so he didn't take Stiles too serious and end up looking like a fool.

"Sorry for the delay, who ordered the soup of the day?" asked a voice, and Derek felt a jolt of recognition flash through him. _It couldn't be._ Stunned, he looked up into brown eyes and a warm, sweet smile.

"Jennifer Blake?" Derek asked, rising to his feet. Surprise flashed over her face, and the recognition widened her smile.

"Oh my god! Derek Hale!" she squealed, throwing her arms around him in a tight hug before stepping back to look at him, holding his hands in hers. "It's been forever! How have you been? What in the world are you doing here?"

"Fine! Good," Derek answered, flustered. He couldn't believe she was here in front of him. "I grew up here. I was with the NYPD after graduation and recently decided to come home. Never mind me, what are _you _doing all the way out here? I would have figured you to be somewhere running a big city department division yourself now, not waiting tables."

Jennifer smiled, deepening her dimples. "Well, you know how things can change. I had some things happen in my life that majorly changed it, and decided to quit the police force. So here I am."

"Oh. I see," said Derek, feeling somewhat deflated. She wasn't even an officer anymore. He had once envisioned her as his partner in all things, but now he felt he hardly knew this woman standing in front of him—if he ever really had. Her hug had been warm and friendly, but not much more than that. It hadn't felt anything like he had thought holding her in his arms would feel like. Certainly nothing like he'd felt when...

"Oh, god, I'm so sorry, I'm being rude," Derek said with a start, remembering he wasn't there alone. "Jenn, these are my partners at BHPD. This is Detective Scott McCall, that's Detective Isaac Lahey, and this is Dr. Stiles Stilinski, our head of forensics." he turned to his companions. "This is Jennifer Blake. We went to police academy together." He smiled at her. "She was one of the best in class. Everyone always said so."

"Oh, you!" laughed Jennifer.

Scott and Isaac both gave her friendly smiles and greeted her pleasantly. Stiles, on the other hand, looked at her unsmilingly with narrowed eyes. "Charmed, I'm sure," he said, sounding almost sulky.

"Well! I best get back to it!" Jennifer said, smiling at Derek again. "It really was great to see you again, Derek. I hope you won't be a stranger!" She squeezed his hands a final time before letting go and returning to the kitchen.

Derek sat back down in the booth, feeling blindsided. Jennifer was here, in Beacon Hills! She had quit the police force and was, of all things, waiting tables. It was so different from the driven cadet he'd known in academy. Derek ate his food methodically, so lost in his thoughts that he didn't notice that Stiles barely spoke the remainder of the meal and hurriedly excused himself after paying his tab.

The next day when Derek went to the lab to check on a status report for some evidence gathered on a case they were working, he was surprised to be greeted by Danielle, who said she was one of Stiles' assistants.

"Dr. Stilinski is off today," she explained pleasantly as she printed the report out for Derek.

"Is he alright?" asked Derek, aiming for casual and not so sure he achieved it. It was unusual for Stiles not to be in the lab while in the middle of a case.

"Oh, I'm sure he is. We all need a day every now and then," Danielle replied easily.

Derek returned to his desk and made himself concentrate on work. When he finally stopped to stretch and hit the water cooler, it was nearly time to go home. Scott cleared his throat and Derek turned to look at him suspiciously, raising an eyebrow.

"Hey, listen, Derek, I need a favor," Scott said, looking sheepish.

"No," Derek said flatly, standing up and putting his coat on.

Scott jumped up and came round the desk. "Dude, please! I swear it'll only take you a few minutes. I just need you to swing by Stiles' place and drop off this bag." He gestured to a bag beside his desk. "Mom sent him some dinner and normally I wouldn't have a problem taking it myself, but I promised Kira I'd be at her place by 5:30 tonight for us to go to a function for her job, and I won't have time to go by Stiles' place first and still make it on time."

Derek stared at him silently with one brow raised, sure judgement was written all over his face.

"Come on, Derek," Scott wheedled. "Be a pal. I know Stiles will be happy to see you. It'll probably make him feel better!"

The reminder that Stiles was out and possibly unwell was enough to weaken Derek's resolve. But he would be damned if he would let Scott know that. "Fine, whatever!" Derek groused. "But I'm about to start charging a courier fee every time you ask me to do something like this. Nowhere in my job description was it listed that I would be your personal messenger boy. Besides, now you have that rookie, Greenberg, to send on your fool's errands." He didn't bring up the fact that Greenberg had already, in his first week, broken the photocopier, caught his tie in the shredder and nearly strangled himself, and tripped over his own feet and spilled hot coffee on Assistant Chief Deputy Finstock. The man still went apoplectic whenever the unfortunate rookie came into his sight.

Scott grinned sunnily at him. "Thanks, Derek, you're the best. I'll make it up to you one day, I swear. Here's Stiles' address, he lives in that new condo unit near the edge of town. You have to have a pass code to get in, so I wrote mine down for you. Stiles will have to give you one if you want. Anyway, I gotta get going." He handed Derek a piece of paper and the bag of food, saluted him jauntily, and left.

Derek sighed and wondered when exactly it was that he had managed to lose control of his life. He typed Stiles' address into his phone's GPS and saw that it was just a few miles from the station. Driving there didn't take long, and soon Derek was entering Scott's entry code on the keypad to get into the parking lot. The condos were fairly new, having been built not long after he left Beacon Hills. The grounds were nicely kept and everything looked modern and neat.

He took the elevator to the floor Scott had indicated. Derek rang Stiles' doorbell and stood there, shifting from one foot to the other. When the door opened, Stiles stood there. He wore a t-shirt that said 'stud muffin' and left his tattoos partially exposed, and red track pants. His feet were bare. He looked comfortable and perfectly well and Derek felt annoyed that he'd had a moments concern in the first place.

"Derek? What are you doing here?" Stiles sounded surprised. "Are you okay? Is there something wrong?"

Derek felt stupid for having been talked into coming. "You weren't at work today," he began.

Stiles gave him a sunny smile. "Were you worried about me? That's so sweet!"

"Don't flatter yourself," Derek scowled. He thrust the bag towards Stiles. "Scott sent me to deliver this. He was supposed to come himself, but he had a date."

Stiles' smile wavered briefly, but returned when he looked in the bag. "Aw, yes! Melissa's chili!" He moved to the side and beckoned Derek inside. "Come on, dude. At least stay and eat dinner with me. This is Mama McCall's famous homemade chili, and it may be one of the closest things we have to a non-sexual orgasm."

"That's not necessary," Derek replied stiffly, refusing to let his mind linger over thoughts of Stiles and orgasms. That was dangerous territory; therein lay madness. "I just swung by on my way home, I've got stuff at home I can heat for dinner."

Stiles looked outraged. "Derek Hale, if you go home and eat canned ravioli because you're afraid to stay at my place—"

"I'm not afraid," Derek snapped irritably. It seemed Stiles never failed to get under his skin. He stomped into the entryway with a huff. "Thanks for the invitation." He knew he sounded ungracious; his mother would have given him a good nip to remind him of his manners.

"No, no, thanks for joining me," Stiles said, eyes twinkling. "You won't regret it, I promise. I just so happen to have a bag of Fritos in my cabinet and shredded cheese and sour cream in my fridge. Give me a few minutes to heat this up, and I'll feed you a meal worthy of the gods."

"I never heard of the gods eating chili before," Derek said dryly as he removed his jacket and hung it over the back of a chair in the living room. His tie joined it, and he decided to loosen his shirt buttons and roll up his sleeves. No reason why he shouldn't at least make an attempt to be comfortable. He looked around the living room, impressed with the decor.

"Shush," called Stiles from the kitchen. Derek could hear the clattering of a pot on the stove and cabinets opening and closing. "If the gods had eaten Melissa's chili, they might still be in power."

Derek couldn't help huffing a soft laugh. He walked into the kitchen, which was tasteful and had state of the art appliances. Stiles hadn't struck him as the type to have a posh place such as this; Derek had fully expected a cluttered and sparsely decorated bachelor pad with video game and movie posters on the walls, similar to what he had in his office space.

The air was starting to smell heavenly, the scents of rich spices and meat making Derek's mouth water. He made himself comfortable at the kitchen table, which was already set for two, and watched as Stiles poured a small amount Fritos into bowls, topped them with chili and then added generous amounts of shredded cheese, as well as a dollop of sour cream to each serving.

"Want a beer?" asked Stiles as he carried the bowls over to the table, placing one in front of Derek and the other at the other setting. He walked to the refrigerator and reached inside.

"Sure," Derek said, nodding his thanks as Stiles handed him one. He stirred his bowl, mixing everything together, and took an experimental taste. Stiles was right, the chili was incredibly good. He couldn't stop the small noise of pleasure he made.

"Toldja," Stiles said smugly as he sat down and stirred up his own bowl. They ate in silence, the only sound their spoons scraping against the bowls. When the food was gone, Stiles suggested they move to the living room, and they sat on the couch in front of the television. The game was on, and it provided background noise as they relaxed.

Derek tilted his head back as he finished off his beer. He was pleasantly full and, to his surprise, enjoying Stiles' company. "I like your place," he said.

"Thanks," Stiles answered. "My mom was from a pretty well off family, and when I was born, my grandparents set up a trust fund for me to have when I turned eighteen. I earned a full ride to school, so I didn't have to touch it for that, but I bought this place for me and Lydia to live in when we got married."

"I see," Derek said cooly. That explained a lot, if it had been designed with Lydia in mind.

Stiles turned on the couch so that he was facing Derek. "So, I was curious. What's between you and that waitress at the diner?" he asked.

Derek hadn't been expecting this particular turn of conversation. "Why do you ask?" he hedged.

Stiles shrugged a shoulder. "You just looked so happy to see her. She must be fairly new, I don't remember seeing her there before."

Derek fidgeted in his seat. "We were students at police academy together. She was a real go-getter, one of the best in our class. I always admired her." He didn't add that she had reminded him of his first love. "I was shocked to see her here. I honestly figured whenever I found her again she would be heading a department of her own."

"Ah. I see. So you're in love with her," Stiles stated with a small sigh.

Was he? Derek once thought he knew exactly what his feelings for Jennifer were, but now he wasn't so sure. He huffed out a short laugh. "Is that what it is?"

"Hmmmm," Stiles said evasively. He studied him silently for a moment, then cleared his throat. "Hey, wanna do a quick psychology test?" he asked with a mischievous grin. "Nothing official, just having fun."

Derek felt confused by the request, but he wasn't really wanting to continue discussing Jennifer, either. "Fine," he agreed.

"Okay, first question: you're looking for something. Are you looking for a key, a pet, your checkbook, or a bottle of tums?" Stiles asked.

Derek thought for a moment. "Hmmmmm. The tums. No, wait, make it a key."

"Interesting," Stiles mused. "Seems right now you're worried about love."

"I am not!" protested Derek, feeling his cheeks flush.

Stiles held up his hand. "A key symbolizes love. The tums symbolize a secret. The check book is for money, and a pet is for social life." he said, ticking off his fingers.

Derek shook his head, resolutely ignoring those capable hands and the tattooed forearms they lead to. "Well, that's wrong," he stated huffily.

"Next question," Stiles said, ignoring him and moving on. "I'm going to call out a few names. These people will be signified by one of my fingers. I want you to show me which one." He held up his hand again, fingers splayed wide. "My dad. Chief Stilinski."

Derek stared at Stiles for a moment, then decided to play along. He reached out and tapped Stiles' thumb.

Stiles smiled, pleased. "The thumb signifies respect. That's cool. Okay, how about Scott?"

Smirking, Derek tapped Stiles' middle finger.

"The middle finger means friendship," grinned Stiles. "Just whatever you do, if Scotty asks you to pull a finger, don't. Not if you wanna _remain _friends. Moving along, now. What about Jennifer?"

"Why Jennifer?" asked Derek with a small frown.

"Why not?" countered Stiles. "It's just a game, right?"

Derek rolled his eyes. "Sure, a game," he muttered as he considered Stiles' hand again. After a moment, he reached out and tapped the index finger.

"Damn it, I just _knew_ it," mumbled Stiles, low enough that were Derek not a werewolf he probably wouldn't have been able to understand him. Derek was confused by his reaction, but before he could ask about it, Stiles wiggled his fingers again. "What about me?"

Derek reached out and without really thinking about it, tapped the index finger again.

Stiles blinked. "Wow, no hesitation, huh," he said, sounding smug. "Now the final question. An unknown person is trying to get into a room. They're trying to open the door with a key. Who are they? And will they be able to get in?"

"This suspicious person sounds like you," Derek tossed back. "and I'm sure you'll get that door open, be it with a key or you just forcing your way in."

"Very interesting, indeed," Stiles said, sounding far too self satisfied for Derek's liking.

"Are you going to enlighten me?" Derek asked sardonically.

"We have just conducted a subconscious test," announced Stiles. "And you may not realize it, but you're totally in love with me."

Derek's jaw dropped in astonishment. "What the hell are you talking about?" he demanded.

Stiles waved a hand. "You probably don't realize it yourself, yet. You chose the index finger for me. That symbolizes the one you love."

"Have you forgotten I chose that finger for Jennifer as well?" protested Derek.

"Yeah, but you hesitated before doing so, whereas in my case you picked that finger right away," Stiles countered. "Plus, there's the final question. The room is the heart. You see me getting in there."

"What about the key?" asked Derek distractedly. Surely this was just a parlor trick that didn't mean anything.

"My dick," Stiles said with a wicked grin. "But you said I'd get in with or without a key, so while you wouldn't mind me fucking you, you'd like to fuck me as well."

Derek's mind was whirling, trying to keep up. "I can't believe I'm listening to this," he snapped, jumping up and stomping over to the chair where he'd laid his coat and tie. He never should have stayed.

"Derek, wait!" Stiles said from right behind him. When Derek whirled around to face him, Stiles slid their bodies together, locking their mouths.

Derek felt the blood pounding in his ears as Stiles encouraged his mouth open. He shuddered as he felt Stiles lick his way in, exploring gently and sliding his tongue over Derek's own. He tasted faintly of spices and beer, and Derek swallowed back a moan when he felt those long fingers work their way into his hair and give a gentle pull.

Without knowing how he got there, Derek found himself sitting in the chair with Stiles astride his lap. His hands held tightly onto Stiles' hips, and he was surprised to discover his claws had popped out without his realization. Stiles nipped at his lower lip before sucking on it gently, and when he ground his hips against Derek, rubbing their hard cocks together, Derek tossed his head back with a groan.

"Derek," whisper Stiles hoarsely, caressing his cheek with one hand. "Won't you please let me in?"

Derek stared back at him. Stiles was panting softly, his eyes looking a shade darker and pupils wide. Derek felt sure his own eyes were glowing red. He didn't really understand what it was between himself and Stiles, but whatever it was, it was far more powerful than he had even realized.

"I haven't, that is, I've never—" Derek stammered.

Stiles' eyes widened in surprise. "Jesus. You actually _are _a virgin? I just figured you were in a dry spell. Like there's no way anyone as hot as you could possibly be—"

"I'm not a virgin, damn it," Derek snapped heatedly as he pushed Stiles off his lap and stood up. He resisted adjusting himself in his slacks. "I just don't have a lot of experience with guys." It was true. Other than the mutual hand jobs with his college roommate, he'd never fooled around with any other men. His first time had been with Paige, and they had only done it a few times before she'd been tragically killed. He didn't like to think about Kate; memories of her left him feeling dirty and betrayed still to this day. He'd gone on a few dates in college, hooked up here and there, but hadn't ever connected with anyone. When he'd entered academy, he'd been gone on Jennifer from the moment he'd laid eyes on her. Now he was beginning to realize she had been nothing more than a fantasy he'd built up, something to remind him of the time when his life had been simple and yet untouched by the tragedy it later became.

He recognized the heat low in his belly as desire, but Derek had learned from hard experience what thinking with the wrong head got him. Stiles kept him so off kilter already, the idea of letting him see him completely vulnerable was incredibly unnerving, and honestly terrifying.

Somehow it seemed Stiles understood his hesitation. "Derek, listen. I know I've pursued you pretty aggressively up til now, and there were times I was inappropriate. I'm really sorry. You don't really have any reason to trust me, but I won't hurt you. I swear it," he said softly. "We won't do anything you don't want to do, okay? If you say stop, we stop. I just want you to feel good."

Derek could hear the sincerity in Stiles' voice and knew he was being truthful. Suddenly he was tired of resisting the pull he felt anytime he was around Stiles, tired of denying the attraction he felt. It was becoming obvious to him now that Jennifer had truly been nothing more than an unattainable fantasy. She had seemed pleased to see him, but nothing beyond that. It was foolish to keep pining over someone he would never be able to have, wasn't it? Especially when he had the chance to have something real and palpable and within his reach.

The honey eyes that had been watching him carefully widened when Derek nodded imperceptibly. He felt Stiles cup his face gently and closed his eyes as Stiles leaned in to touch their foreheads together.

"I promise, I'll make it good for you," Stiles whispered as he took Derek's hand and led him down the hallway to his bedroom.

Derek glanced around briefly, if for nothing more than to look anywhere else but at Stiles. He wasn't used to feeling flustered or embarrassed, and it made him almost uneasy. Stiles' bedroom was surprisingly neat, decorated in browns, reds, and creams that Derek rather suspected were remnant of his relationship with Lydia than of his own choice. The bed was unmade and piled high with pillows, as though Stiles had been lounging in it at some point during his off day.

When Stiles gently pushed at his shoulders, Derek sat on the edge of the bed. He could hear his heartbeat pounding in his ears and wondered if it was audible even to Stiles' human hearing. He tried not to flinch when Stiles sat down a short distance from him, close enough to be within reach but not close enough to be touching at the moment.

"You really are beautiful, Derek," Stiles said quietly. "I always thought so, you know. Let me take care of you tonight. Let me show you." He reached out and held his hands flat against Derek's chest, rubbing his pectorals and dragging the material of his shirt over the sensitive skin of his nipples. Derek caught his breath as the sensation ignited nerves all over him, places Stiles hadn't even touched yet. He could feel his cock hardening, even as nervousness and anticipation combined to nearly overwhelm him. Part of him wanted to chicken out, to get up and run away, another part wanted to beg Stiles to never stop touching him.

"We'll go slow. If I do something you don't like, just tell me," Stiles said. He tugged lightly on Derek's shirt. "Will you take this off for me? Or would you rather I did it?" When Derek hesitated, he smiled gently. "If you'd rather, you can leave it on, I suppose, even though that's a real tease. I'd really like to see all of you. Make sure I didn't make anything up in my head from our time in the shower!"

Derek began unbuttoning his shirt, fumbling slightly with the buttons. He felt awkwardly self conscious and huffed, "Fair's fair, you know. You need to lose your shirt, too. I shouldn't be the only one giving a show."

"Hey, you're right," Stiles agreed with a saucy wink, reaching down to grab his shirt at the waist and quickly divesting himself of it. "Better now?" he asked.

"Ummm, sure," Derek croaked. He stared for a moment, arrested by the tattooed skin on display. Up this close, they were even more intricate and defined, the symbols and runes starkly defined against his paler skin. He had been too embarrassed and distracted in the shower to pay attention.

"Now maybe my eyes deceived me," Stiles said conversationally, "but I'm pretty sure I saw a tattoo on you as well. Am I right?"

Derek nodded as he tugged the final button free on his shirt. "I have a triskelion on my back."

Stiles eyed him shrewdly. "That's a hell of a process you wolves go through to get tattooed. I have the dubious honor of holding Scott while he got his, and let's just say I'd rather not dwell on it that much."

Derek shrugged. "It was for my family," he said simply. Stiles seemed to understand that he didn't really want to talk any more about it; but Derek was curious. "What about you? Didn't all those hurt? I've heard the ribcage is a real bitch to tattoo."

"I'm not gonna lie and say it didn't hurt like hell, buuuuut let's just say a little magic makes the process a little easier," Stiles replied with a wink. "But we aren't here for me right now. I want to know about _you._"

Derek was surprised to find himself laying back on a fluffy pillow without realizing how he got there. Stiles stretched out next to him, propped up on one elbow, and Derek was extremely aware of the warmth radiating from his skin.

"So, Derek Hale," whispered Stiles, leaning over him to whisper hotly in his ear, "what do you like? Where are your most sensitive places? What turns you on? Is this the place?"

Derek closed his eyes, barely suppressing a shiver as Stiles' hot breath teased his ear. He nearly jumped when he felt a warm tongue tracing the outer shell of his ear before there was a sharp nip at the lobe.

"Or maybe here, instead," Stiles continued, licking down the corded muscle of Derek's neck. Derek felt Stiles rub his cheek against his rapidly heating skin before sucking at the juncture where neck and shoulder meet, bringing blood to the surface, and couldn't hold back a low moan. Stiles was marking him, _scenting_ him, something no one had ever done to him before, and it was more erotic than he'd ever dreamed.

"Such a shame," Stiles remarked, sadly watching as the bruise he'd made on Derek's throat rapidly healed and faded away. "I would have liked to see you walking around with a hickey, knowing I was the one who put it there." He shifted and moved a bit lower. Derek felt the tingle of his fangs threatening to pop out as Stiles began nuzzling one of his nipples, teasing with the tip of his tongue before laving the surrounding skin. As he worked the one with his tongue, he lightly pinched the other, the dual sensations nearly driving Derek mad. When it seemed he could bear no more of the blissful torment, Stiles switched his hand and mouth from one side to the other. He blew against the damp skin, cooling it and making the sensitive nubs harden further.

"God, Stiles," Derek stammered, which was actually more coherent than he'd thought he'd be able to manage.

"Don't hold back," ordered Stiles as he licked his way maddeningly downward, alternating nips and suckles over the definition of Derek's belly. "I want to hear every sound you make. I want to know if I'm giving you pleasure."

"You are such an ass sometimes," Derek ground out, but it lacked any force behind the words. He felt Stiles tugging his belt loose and within a breadth of a moment, his slacks were sliding down his legs and off his body. Feeling ridiculous lying there in just his briefs and socks, Derek quickly toed the socks off.

Stiles studied him, eyes bright with heated admiration. "Stunning," he whispered reverently. Derek felt himself flush and resisted squirming under the intensity of his gaze. Stiles tucked his fingers in the elastic waistband of Derek's briefs and he looked closely at Derek. "May I?" he asked.

Taking a deep breath, Derek nodded. He closed his eyes and forced himself to lay still as Stiles tugged his briefs off, freeing his hard cock from its final confines. He hardly dared to move or even breathe, knowing Stiles' observant eyes were on him, even though he kept feeling the urge to cover himself protectively. It felt strange to be lying there, totally bare and vulnerable, completely exposed while Stiles still wore his track pants.

"You truly are magnificent," Stiles said, sounding awed. Although this wasn't the first time Stiles had seen him nude before, Derek couldn't help but feel pleased that he could evoke this response. Stiles shifted slightly, and Derek heard a drawer open and close. A soft click, followed by a liquidy squelching sound and the light scent of strawberry came next. When long, nimble fingers wrapped around his cock and began slowly stroking him, Derek couldn't stop the low groan of pleasure from escaping his throat.

"I'm guessing you've had a blow job before," Stiles remarked casually, and Derek would have laughed, because leave it to Stiles to turn this into one of his lectures; except the hand stroking his dick was doing amazing things and he was no longer sure he knew exactly how to words properly. "A good blow job can be mind shattering, to say the least," continued Stiles, "but sometimes just sucking isn't enough. Stroking like this can bring a man to climax, and when combined with sucking can feel utterly amazing."

"Hnngghh," Derek agreed with grunt, eyes rolling back into his head as Stiles' other hand slid down to cup his balls and gave them a gentle squeeze.

"Mmmmmmm, yes. Such a lovely sound," Stiles sighed happily. "So, a lot of people tend to neglect these, which is a real shame," he said as he continued to fondle Derek's balls lightly. "As long as one is careful, the testicles can be a source of great pleasure. You can tease them with your fingers, suck them gently into your mouth, and there's a place right about here—" he pressed lightly just below the sac and Derek hissed as he felt his nerve endings sizzle. "Yeah, right there, that spot likes to be gently massaged or lightly scratched. Combining that with nice suction and tongue moves and you have a winning combination. Allow me to demonstrate."

Derek had only a second to breathe in before an amazing, moist heat surrounded the head of his cock._ Jesus. _He'd known Stiles had a mouth created for blowjobs, but he had not been prepared for anything like this. As Stiles moved his mouth up and down, he swirled his tongue around the head then licked along the shaft. One hand was wrapped around the base, stroking in rhythm with that talented mouth, the other had moved below his balls, and Derek could feel Stiles massaging the sensitive area there. Then Stiles applied pressure at the same moment his tongue did something to his dick that was purely sinful magic, and unable to hold back, Derek came with a hoarse shout as an explosion of white light burst behind his closed eyes.

He lay there in a daze, panting as he tried to catch his breath. He wasn't even sure he knew his own name at that moment.

_Tyler._

_Dylan._

_No, Derek. That was it. His name was Derek._

Derek felt wrung out and sated all at once. He couldn't remember if he'd ever come so hard before, and that had only been from Stiles sucking his—

Oh, damn.

Derek felt some of his post orgasmic high disappear. He opened his eyes quickly and turned to look at Stiles, who was laying next to him with a gentle smile on his face. "I'm so sorry," he gasped. "Everything felt so good and before I knew it, I was coming. I didn't get to warn you to move away or anything."

"No apology necessary. I'll take it as a complement," Stiles said, voice husky and making Derek's wolf preen in satisfaction even while Derek fidgeted in embarrassment. He seemed cheerful and not at all disappointed or put out. "Wolves are clean, so I wasn't too worried, really. If I was concerned about come in my mouth, I have flavored condoms I could have used when we got started. We're totally cool, okay? Besides," he continued with a devilish grin, "I'm really enjoying educating you in some of the finer things in life."

Well, Derek felt he couldn't really argue Stiles' smug comment, not when he was still reeling from his orgasm and not really sure he could feel all of his toes yet. He eyed Stiles warily as he moved to straddle his hips. The fabric of Stiles' track pants brushed against his sensitive cock, and Derek hissed softly at the slight overstimulation.

"A man has erogenous zones all over his body," Stiles said conspiratorially, as though sharing a great secret. "Some people don't realize that a man's nipples can be sensitive like a woman's." He reached down and gave Derek's nipples a tweak, eliciting a soft moan from him. "Hmmm, yes. And of course, the neck is another sensitive area, as we already discovered." He nosed along Derek's neck again, the blatant scenting making Derek want to howl. Shifting slightly, Stiles reached back and ran his clever fingers teasingly along Derek's inner thighs, grinning when he felt the flex of muscle there. "This is another area men like to have attention paid to, be it light touches or even bites or suction."

Derek stared at him, beginning to breathe more heavily and about to decide that Stiles was determined to slowly and torturously drive him out of his mind. He was not going to survive this; he was ill-equipped emotionally to deal with a too-brilliant-for-his-own-good-and-too-sexy-for-Derek's-peace-of-mind forensic scientist who currently looked like he'd crawled out of one of Derek's most illicit wet dreams. His cock was beginning to show signs of renewed interest in the current situation. When Stiles shifted to the side again, Derek thought he was finally being granted a small reprieve.

"And then there's this," Stiles continued.

The thought flew out the window entirety when Derek felt a gentle pressure pushing against his asshole. His whole body lurched in shock.

"What are you—wait, I don't think—" Derek stammered, leaning up and scooching back against the pillows, away from the questing finger.

"Hey, hey, it's okay," Stiles soothed, moving his hand away and kneeling up on his knees, looking concerned. "We won't go any further if you're uncomfortable. I was just going to say that the prostate is an erogenous zone as well, and many men never experience the pleasure of stimulation there."

Derek maneuvered so that he was leaning back against the headboard. He needed to be able to organize his thoughts. Things seemed to be happening so quickly, yet it somehow didn't feel wrong, either. But Derek had been fooled before and it made him wary. He eyed Stiles curiously. True to his word, Stiles had stopped as soon as Derek had shown any misgiving. He hadn't tried to pressure him or shame him. Come to think of it, Stiles had yet again turned it into a sort of educational thing. And then there was the fact that Derek couldn't smell him. No arousal or desire, nothing. This ability of Stiles' to mask his scent added to Derek's underlying confusion.

Maybe he wasn't as into it as Derek had been?

"What about you?" Derek blurt out before he realized he was going to do so.

Stiles blinked at him in confusion. "Me?" he asked.

Derek shrugged a shoulder, feeling a bit stupid and awkward for even asking. "Are you enjoying this? Touching me, I mean?"

A wry grin formed on Stiles' lips. "Oh, Derek, believe me," he said, gesturing to his crotch where his hard cock was tenting his track pants.

Derek wasn't sure which felt stronger; relief that Stiles was as affected as he was, or guilt that he'd done nothing in return. "Here, let me help you out with that," he murmured, reached out to grasp Stiles' erection. His jaw dropped open in shock when Stiles playfully popped his hand.

"Hup, hup, hup," Stiles scolded, twisting away out of Derek's reach. "This isn't a trade off. I did this because I wanted to pleasure you and make you feel good, not because I expected something in return." He met Derek's wide eyes with a small smile. "I can wait until you're ready for me."

Derek felt an insane urge to argue; what made Stiles think he wasn't ready for him now? But Stiles anticipated him. He held up a finger in admonishment. "No, Derek. Believe me, I have so many things to teach you. We'll take things nice and slow." He leaned forward and kissed Derek softly, almost chastely, the kiss sweet and tantalizing and leaving Derek hungering for more.

"Stay with me tonight?" Stiles whispered, nibbling at Derek's lower lip. "I'm a world champion cuddler and make a kick ass breakfast. Plus, we can make out until we fall asleep."

"Well, how am I possibly to resist such temptation?" Derek drawled, rolling his eyes and smirking when Stiles huffed and smacked his shoulder. "Fine. But I expect more than pop tarts for breakfast."

Stiles held a hand to his chest in mock outrage. "I would never! Just for that, I call dibs on the first shower." He got up off the bed and flounced dramatically to the en suite bathroom.

Derek lay back against the pillows, one hand behind his head, the other idly rubbing his belly. This had been a night of unexpected surprises, to be sure. He wasn't even sure what had possessed him to agree to stay the night. If he had an ounce of the good sense his mother always claimed he'd inherited from her, he'd get dressed right now and go home to his own bed. Somehow, though, the idea of his loft apartment seemed cold and unappealing.

What had he gotten himself into?

* * *

><p>Monday morning found Derek sitting at his desk, yawning and blinking blearily as he stirred his coffee.<p>

Friday night with Stiles had stretched into all day Saturday and then overnight again. Last night when Stiles had asked him to stay yet again, he'd been powerless to say no.

Of course, that could have been because he'd been totally come dumb at the time. Stiles hadn't been kidding when he said he had a lot to show Derek. He had spent the majority of the weekend doing just that. It had been so much more than just earth shattering blow jobs. Oh, yes, Stiles had quite happily spent time sucking Derek's brain out through his dick, but it hadn't ended there. He had also petted and soothed at Derek, relaxing him until he was able to work those nimble fingers inside his ass, slowly and methodically stretching him and working him open. Derek had learned exactly just how enjoyable having his prostate rubbed could be. Then Stiles had taken it up to a whole new level, arranging Derek on his hands and knees and rimming him until Derek actually lost control of his shift for the first time since he was a teenager, popping fangs and claws as he morphed into beta form. He now owed Stiles a new set of sheets, damn him, but if there was truly such a thing as a religious experience, Derek was pretty sure that was what he'd had.

Even that morning Stiles had woken him just before the alarm by stroking him to full hardness then swallowing him down. He'd lost count of how many times he'd come over the weekend. It had to be a personal record; Derek wasn't even sure if he'd ever come that much in a short time, even as a horny teenager. Certainly his hand had never been that pleasurable, any comparison wasn't even close.

Yet no matter how many times he'd brought Derek to orgasm, Stiles steadfastly refused to let Derek return the favor. He definitely been hard and surely it had been painful after a while. He had spent a long time in the shower each time he'd gone in, and Derek was positive that Stiles had jerked off while using magic to soundproof the bathroom so Derek couldn't hear him. Instead of easing his mind, Derek actually felt more confused than ever. Paige had always been eager for his touch, and Kate had made no secret of her lust when she'd played with his body. So what held Stiles back from going any further? It wasn't like Derek wasn't willing.

"Morning!" chirped Isaac cheerily as he strolled into the office. He took of his jacket and unwound his scarf, eying Derek's coffee lustfully.

Derek moved his coffee protectively closer, ignoring Isaac's pout. "Morning," he answered.

Isaac stared at him, grinning and looking like he was anticipating something. Derek stared back, starting to feel irritated after a moment. "What?" he snapped.

"Stiles told Scott you stayed with him all weekend!" crowed Isaac jubilantly. "Are you two a thing now or what?"

"I—he said—how do you know we weren't playing video games and just hanging out?" Derek demanded, flustered and feeling the heat rising up his neck.

"Your reaction says it all," Isaac said cheekily. "If you were forming the bromance of the century you wouldn't be this embarrassed by me asking." He reached out and patted Derek's shoulder. "It's totally cool, by the way. I'm happy for you. Who knows? Maybe you'll be a good influence on him and he won't be so damn annoying."

While part of Derek wanted to defend Stiles against such words, his mind was still reeling. They hadn't really talked about what exactly they were, and the last thing he'd expected was to hear about his personal life at work. "Excuse me," he growled, shoving his chair back and striding out of the office, leaving an obviously startled Isaac behind. He went straight to the lab and practically threw the door open. "Stiles!"

Stiles looked up from his desk, surprise giving way to a warm smile. He had on jeans and some sort of graphic t-shirt on under his lab coat, and Derek was further frazzled to see those annoyingly perfect lips wrapped around the stick of one of his ever present suckers.

"Derek! What's up?" he asked.

Derek nearly growled. "What's up? What do you mean, what's up?"

Stiles frowned in confusion. "I'm not sure I follow you."

"You told Scott I stayed with you this weekend!" snapped Derek.

A look of hurt flashed across Stiles' face before he carefully schooled it into a neutral expression. "Well, he _is _my best friend. Additionally, we work together and technically he's your boss. I just figured it made sense to let him know. If I'd known you wanted to keep it a secret—"

"No, that isn't it!" Derek wanted to bang his head on the desk in frustration. Stiles was taking it the wrong way and the situation was quickly spiraling out of control, if it had ever even been _in _control. He took a deep breath. "Look. We didn't talk about things, and I didn't know where we stood or what exactly we're doing. I still don't. So I wasn't expecting Isaac to come in congratulating me on my new relationship when I don't even know what's going on."

Stiles' eyes filled with understanding and remorse. "Ah, damn. I should have known. I'm sorry, Derek. I didn't tell Scott to keep it on the down low, and Isaac has been his work partner for over a year now. There are times their lives have depended on each other, and I'm sure he told him since you're now a partner, too. What affects one of you can affect all of you. I didn't think."

Derek rubbed the back of his neck, wondering if he'd overreacted entirely. "I get it," he finally said, sitting down in one of the office chairs. "I don't want you thinking I'm ashamed of what we did, or trying to keep it a secret. I just don't know quite what to make of it myself, and that makes me feel...I don't know, unsettled somehow, I guess? And I'm not used to that." He reached out a hand and waited for Stiles to put his own hand in it, then tugged him gently until he was sitting in his lap. "So, what are we, Stiles? What are we doing?"

Stiles perched sideways on Derek's lap and gave him an earnest smile. "We're getting to know each other," he said.

Derek raised a wry brow at him. "You had your tongue in my ass less than 24 hours ago. I'm pretty sure you may now know me better than even some of my closest friends," he smirked.

"Why, Detective Hale, such filthy words coming out of this lovely mouth! It's positively shocking," Stiles jokingly replied as he leaned down close enough for Derek to admire the lush lashes framing his stunning eyes, and the light pattern of moles sprinkled on his skin. The quick smack on the lips wasn't enough for either of them, and after a thorough kiss, Derek was not entirely surprised to find himself with Stiles' sucker in his mouth.

"So, dinner tonight, maybe?" Stiles asked. "I'm sure I could throw together something palatable. Or we could order in, if you prefer. Plus, I have Netflix! I need to get caught up on The Walking Dead."

"There's no such thing as zombies," Derek stated with an eye roll as he stood up, taking the sucker out of his mouth and popping it back into Stiles'. He watched with unabashed interest as Stiles suggestively swirled his tongue around it before shifting it to the side of his mouth.

"So says the werewolf," drawled Stiles. "Kind of ironic, huh?" He clapped his hands briskly. "Now, time to go. As much as I'd love to have you here all day, I'd be too distracted by all your pretty, and I have a ton to do. Jared's a decent lab assistant, but he barfs at the drop of a hat and I end up having to do all the work myself anyway. Besides, I'm sure Scott's come in by now, and there's been a possible selkie sighting that needs investigating. Go do manly cop things, Detective, and I'll see you tonight."

As Stiles turned to go back to his desk, Derek caught his hand and tugged him back to him. Wrapping his arms around Stiles' waist, he kissed him hungrily, allowing his hands to slide lower and cup the firmness of his ass and lifting him against him ever so slightly. While Stiles still hadn't exactly defined them, Derek decided it didn't hurt to give him a little food for thought. When he stepped away and let Stiles go, Derek was pleased at the dazed expression on his face.

"Until tonight, Dr. Stilinski," he grinned, turning and walking out of the lab, feeling immensely self-satisfied.

When Derek got back to his desk, Scott had come in, and he and Isaac were waiting to go investigate the selkie Stiles had mentioned. Scott raised a brow at Derek's slightly mussed appearance and puffed lips but didn't say anything. Isaac just gave him a shit eating grin and confessed to stealing the coffee he'd left behind when he'd stormed out earlier. Derek couldn't find it in himself to be mad, calling Isaac an asshole in an almost affectionate manner and getting Scott to agree that Isaac definitely owed him the next coffee.

The investigation ended up being complicated and ran longer than expected. They ended up skipping lunch altogether, and once they finally had the pesky selkie captured and ready for processing, Scott declared himself too famished to carry on.

"Let's go to the diner," he cajoled. "We can call Stiles and have him meet us there."

Derek hesitated. In truth, he'd been looking forward to another night in with Stiles at his apartment. Dinner and zombies, hopefully followed by a heated make out session on the couch. But Scott looked at him so earnestly that Derek rather hated to disappoint him.

"You heard the man, Derek," Isaac chimed in. "Scott's hungry!"

"No, no," Scott shook his head. "I'm not hungry. I'm _hungry!_" he growled, using his Alpha voice. Even though he was obviously teasing, Isaac quickly ducked his head and even Derek felt a little tingle along his spine.

"I'll call Stiles on the way," Scott said cheerfully as they piled into the car.

Roughly an hour later, the four of them were piled in their usual booth. Stiles had been waiting for them when they arrived, sitting behind the wheel of an almost garishly blue jeep and tapping a rhythm against the steering wheel with his fingers, the same fingers that now drummed on the table.

Derek doesn't stare at his fingers. He _doesn't._

"By the way, Scotty, thanks for the idea of sending Lydia flowers to apologize for sneaking into the archive" Stiles said, sounding sheepish. "I think it may keep her from killing me, at least for the time being."

"Until you do something else harebrained and get her on your case again," laughed Scott.

Derek had nearly physically jolted at the mention of Lydia, especially hearing Stiles say he'd sent her flowers. He couldn't help but wonder yet again if part of the reason Stiles seemed rather reluctant to talk about _them _was because he still had feelings for Lydia. Maybe she was the reason Stiles wouldn't get off with Derek, instead seeming to prefer doing it himself.

It was a depressing thought.

"Hey, guys, sorry to keep you waiting!" Kali said cheerfully as she approached their table. Derek was shocked to see her wrist wrapped and a butterfly bandage on one cheek.

"What happened to you?" Derek asked in concern, bring the attention of the others to her.

Kali's smile slipped before reappearing, although it now seemed forced. "I'm afraid I got clumsy and had an accident," she said vaguely. "It's nothing for you fine gentlemen to worry about. It'll heal soon enough." She took their order and promised to get it into the kitchen immediately.

Once she returned to the kitchen, Derek looked across the table at Scott. "That was...odd," he remarked.

Scott narrowed his eyes thoughtfully. "Kali is an Alpha, herself. Seems she should have easily healed from any sort of mishap she had."

Isaac looked at them alertly. "You think she's hiding something?"

Scott shrugged. "It's definitely unusual, let's just leave it at that for now."

They sat somberly quiet after that. When Kali returned, she had their food on a large tray. She was placing the tray on the stand when Jennifer hurried over.

"I'll take care of it from here," she said to Kali.

Kali nodded and stepped back. "I'll see you guys around," she said as she turned and fled to the kitchen with a speed that almost bordered on rudeness.

Jennifer held up a plate. "Who had the patty melt?"

"That'd be mine!" Isaac said enthusiastically, taking the plate from her.

Derek caught her eye and smiled at her fondly. Even if his heart was slowly but surely moving on, he still admired her as a person. Jennifer finished serving them and turned to leave, promising to return with drink refills. As she stepped away, Derek reached out and put a hand on her arm, halting her movement.

"Jenn," he asked seriously, "did Kali really have an accident?"

Jennifer's smile never wavered. "Well, that's what she said. Now you guys let me know if you wanna see a dessert menu when you're finished, okay?"

When she was gone, conversation was a minimum as they all pounced on their food hungrily. Empty plates were stacked on the table as Stiles thoughtfully dipped the last of his curly fries in ketchup, making patterns on the plate. After a moment, he announced, "I think Kali's injuries were made by someone. My guess is either a hunter, or another Alpha. Otherwise she would have healed already. Something's not right."

Any further speculation was interrupted by Scott's cell phone ringing.

"McCall," he answered tersely. He listened for a moment, then said, "We're on the way." He hit the End button and stood up. "There's been a body discovered. Let's go."

Everyone snapped to action, tossing money on the table to cover the bill and a generous tip and then rushing out the door.

Scott put the strobe light on the car and turned on the siren as they peeled out of the parking lot. Within minutes they were outside of the old Beacon Hills First National Bank building. It had been closed for years, ever since the bank had moved to a larger building downtown, and the building was covered in graffiti and showing signs of decrepitude. The old vault inside had once been the site of a killing years ago and had been torn out to avoid any sort of recurrence. It seemed that murder had found the old bank once again, only this time out in plain sight.

Derek saw Vernon Boyd, Erica's husband, interviewing a shaken up looking teenager in a Beacon Hills High lacrosse letter jacket. Boyd looked up, his face grim as he nodded in greeting as Scott, Isaac and Derek approached.

"I was cutting across the parking lot on my way to meet my friend at the bowling alley," he was saying. "I've done it a thousand times before and never seen anything. Then today I was running late and wasn't paying attention until I literally fell over her!"

"This is Liam," Boyd told them. "He discovered the body and called 911 to report it."

"What do we have, Boyd?" asked Scott, face unsmiling.

"Female, mid-20's. Blonde hair, shows signs of defensive wounds. Looks like she fought and fought hard. Fucker snapped her neck," Boyd growled, his eyes flashing gold in the fading daylight.

Scott walked over to the lifeless body on the ground. The evidence crew was already working the scene, and they moved to the side to let him see the victim. His expression went from shock to horror and finally to sorrow.

"Oh, fuck," he cursed. "This isn't good."

Derek started to ask Scott what exactly he meant when he heard Stiles' voice. He hadn't known Stiles had followed them. "Excuse me, coming through, forensics on scene."

Scott's head snapped around. "Stiles, no! Isaac, stop him!"

"Aw, crap," Isaac groaned.

But it was too late. Stiles had come close enough to be able to see the victim, and his face paled as he saw her and pained recognition flooded his features. He rushed forward, only to have Isaac grab him to keep him from coming any closer. Stiles struggled, dragging Isaac with him as agitation made him even stronger.

"Scott! A little help!" Isaac grunted.

"_Heather!_ Damn it, Isaac, let me go, that's Heather!" Stiles yelled, pain and anger thick in his voice. He continued to struggle even when Scott rushed over and pushed him back, joining Isaac's efforts in keeping him back. A low snarl escaped him, and his tattoos began to glow, their light visible even through his clothing.

Scott's eyes flashed red. "That's enough, Stiles! There's nothing you can do! She's gone, and I'm sorry! I'm so sorry!" He wrapped his arms around him and hugged him tightly. "I'm sorry, Stiles. You have to calm down, though. You're gonna end up either having a panic attack or doing something you'll regret. Come on, buddy, don't do this!" When his words didn't seem to have any effect, Scott looked around wildly until he found Derek. "Derek! I need you now! I can't get through to him and I need you to try!"

Derek still had no real clue what was going on, but it was obvious that Stiles was in distress. He quickly moved to Stiles' side and took him from Scott, wincing at the devastated expression that showed no recognition at all. He held him close, stroking his back. "I'm here, Stiles. It's Derek, and I'm right here. Calm down for me, okay? I need you to calm down. Come on, breathe with me. I've got you."

Relief flooded him when after a moment Stiles' tattoos stopped glowing and his body shuddered as some of the tension left his body. Derek felt Stiles' arms wrap around his waist and heard his breathing hitch as he buried his face in his shoulder.

"You okay?" he asked softly.

Stiles nodded against his shoulder, then lifted his head. He was still pale and his eyes shone with unshed tears. "That's Heather, Derek. She's one of my oldest friends. Hell, we grew up together. Our moms were best friends and we used to be inseparable. We kind of lost contact after high school, I mean, I probably haven't talked to her in years, but damn it! She didn't deserve this. No one deserves to die like this, but especially not her."

Derek nodded sympathetically. Losing a loved one to a crime was a terrible thing, he knew from hard experience. Stiles stepped away and walked off a short distance, visibly trying to compose himself. The evidence team was scouting the area for clues and the coroner had arrived and was examining the body. A small crowd of curious onlookers had gathered, and Derek met Scott's worried gaze across the parking lot. He sighed and went to push them back away from the area.

"This is an official crime scene," Derek announced with authority, letting red bleed into his eyes. "Everyone needs to clear out and let the police do their jobs." As the crowd grumbled and dispersed, a movement towards the back of the crowd caught his attention, and he was stunned to recognize Jennifer with her hair pulled into a ponytail and under a baseball cap, leaving the scene.

Derek wondered what the hell she had been doing there. Maybe old training died hard, or she was curious...? She definitely couldn't have been far behind them when they left, either way. Something was very strange about the whole situation.

When he rejoined Scott and Isaac, Stiles had returned. He was kneeling stoically by Heather's body, looking it over with the coroner, Dr. Danny Mahealani.

"It doesn't look like robbery was the motive," Stiles was saying, indicating the jewelry Heather still wore. "Her clothes are expensive and don't look too wrecked, so thus far, there's not any evidence of sexual assault. Have the nails been checked yet?"

"Yes, Stiles," Danny sighed, sounding long-suffering as he indicated the protective evidence bags in place on the hands.

"Well, excuse me for wanting to make sure no stone is left unturned in nailing the bastard who did this," retorted Stiles huffily. He glared at the ground, then looked intrigued. "What's this?" he asked curiously as he picked something up off the ground. "A coffee bean?"

Derek made a warning growl low in his throat and Isaac lowered the camera he was using to photograph the scene. "Damn it, Stiles, you aren't supposed to touch anything, you _know _that!" he snapped irritably.

"Well, you've taken pictures, right?" asked Stiles defensively. "It's only one. And look, there's more coffee beans scattered all around. I need someone to get these things bagged and tagged and to the lab, stat. They may be important!"

It was starting to look like Isaac was on the verge of throttling Stiles with his camera strap. Scott intervened smoothly. "We know, Stiles. We're going to do our job according to the proper protocol, and you'll have the evidence as soon as we can manage it. Just like always."

Stiles fidgeted and looked abashed at Scott's subtle reproof. Derek was torn between irritation and sympathy. He knew Stiles was upset, but he obviously wasn't thinking straight if he was that close to compromising a crime scene. "Why don't you go home?" he suggested to Stiles, not unkindly. "Let us get the scene processed so we can find whoever did this and bring them to justice. You should get some rest, looks like you're going to be busy soon."

Stiles looked like he would resist, then his shoulders slumped and he looked more vulnerable than Derek had ever seen him before. "You're right," he admitted quietly. "I just feel like I should be doing something _now,_ figuring this out for Heather." He straightened up and gave Derek a smile that was a mere shadow of its normal self. "On that note, I'll get out of everyone's hair. See you tomorrow, okay? I'll be in early." He turned to walk away, then stopped and turned back to blow a kiss to Derek before shoving his hands in his pockets and trudging back to his Jeep.

When Derek got home later that night, his apartment seemed too quiet. It certainly hadn't taken him long to become accustomed to Stiles' company. He prowled around, feeling restless as his thoughts continued to spin busily. Seeing Jennifer at the murder site nagged at his brain. Something about it was just so odd that Derek couldn't make sense of it. Pacing in his apartment was grating on his nerves; he wanted to get out and run. It always cleared his head to shift and race through the woods. The edge of the Preserve wasn't far. It would do him some good to get out and run off some tension. Hopefully it would help him think.

Derek drove to the Preserve and parked his car. Anticipation was building in his veins, and he couldn't wait to strip down and free his wolf. But just as he was about to tug off his jacket, he could hear voices raised as though in an argument. He groaned quietly to himself and went in the direction the disagreement was coming from, careful not to make any sound. As he approached, he was surprised to hear two very familiar voices.

"Just leave me alone!"

Derek hears footsteps rapidly approaching and ducked behind a tree. A visibly upset Kali stormed past him on the path, so distressed that she didn't even notice him.

"Kali, wait! Come back!" called Jennifer as she quickly followed. When Derek stepped from behind the tree, she dropped down into a defensive crouch but stood upright in surprise when she recognized him. "Derek?"

"Jennifer," Derek responded, trying to figure out just what he'd stumbled onto. "I just saw Kali headed towards the exit. She seemed pretty upset. Is everything okay?"

Jennifer waved a hand dismissively. "It's nothing. We had a fight. Happens sometimes," she said grimly.

Derek nodded as he aimed for appearing casual. "I was just about to go for a run," he said. They stood awkwardly for a moment, and then Jennifer sighed heavily.

"Well, I'm really sorry you had to see that. I'd love to stay and chat, but I need to go," Jennifer said, looking like she would rather be anywhere else than right there.

"Sure thing," Derek replied as he stepped aside to let her past. "I'm sure I'll see you at the diner at some point."

"Yeah, sure. I'll see you around," Jennifer said as she walked away, heading in the same direction that Kali had fled.

Derek stood and watched until she was out of sight, then stripped down and shifted. His mind was whirling as he ran, trying to fit all the puzzle pieces together. Kali's injuries. The fight between the two women. A killer on the loose. Jennifer at the murder scene. Derek felt sure he had to be missing _something, _otherwise he had a really bad feeling about the conclusion he was starting to come to.

A few days later Derek was sitting at his desk, poring for the fourth time over the coroner's report that Danny had emailed him, looking to see if he had missed any detail that would help him figure the case out. His concentration was broken when Stiles plopped down in the chair across from his desk. They hadn't seen much of each other since Stiles had left the crime scene, and Derek was startled at how somber he looked.

"Hey," Stiles said softly. "I wanted to check on you, see how you're doing. You don't look so happy right now."

Derek rubbed a hand over his tired eyes. He hadn't slept well since this whole thing began. "Jennifer's been listed as the primary suspect in Heather's murder," he stated wearily.

"Oh," Stiles said, not sounding too surprised. He sighed softly and leaned forward. "Well, let's look at the evidence so far, shall we? First of all, there's the coffee beans found at the scene. It's from a specialty store near the old bank. Jennifer was there buying the same brand, and we have both an eyewitness and surveillance film that shows it was around the estimated time of the murder. Next," he continued, ticking off on his fingers, "footprints matching her size were found on the ground near the edge of the parking lot where the body was. My team is working on finding the shoes that caused it, but it appears that they were made by a pair of sneakers in a brand we know Jennifer has."

"I know, I know," Derek growled. He'd read the evidence reports himself. "It looks really bad, but it just doesn't make _sense, _Stiles. None of this actually proves anything. I know Jennifer, she wouldn't do something like that. She was a police officer!"

Stiles looked troubled. "I guess this isn't the time to tell you the statistics of police officers that turned out violent or had the know how to be able to perpetrate a crime."

Derek scowled at him. "I'm fully aware of that. But I went to school with her. She had such a passion for what was right and making sure justice prevailed."

"People change," Stiles said simply. When it was obvious Derek had no answer for that, Stiles heaved a sigh and stood up, reaching into his lab coat pocket. "Here. This should make you feel a little better." He held up a piece of paper that Derek recognized as a specimen report. "We found skin cells under Heather's fingernails. If you find the person that matches them, you'll find your killer."

Derek looked at the report and then back at Stiles. "What happens if it doesn't match any of the suspects?"

Stiles reached out and tugged Derek forward by his tie until their faces were nearly touching. "Then you find me the person it _does _match, Detective! Once we have a match, there's no reasonable doubt!" He leaned in and sealed their lips together, kissing Derek fiercely. "Good luck! Now get out there and get me the evidence we need to nail this bastard to the wall!" He let go and strode to the door to leave. Opening it, Stiles turned back to give Derek a small smile. "You are convinced Jennifer's not the killer. Proving her innocence is also your job, Derek," he said, taking a sucker out of his pocket and unwrapping it. He popped in his mouth and left, closing the door behind him.

Derek stared at the closed door. Stiles had an excellent point. While everything seemed to be pointing to Jennifer as the killer, Derek was positive that somehow they were missing a crucial piece of evidence that would point them in the direction of the true murderer.

Two nights later he tossed the case file across the coffee table in Stiles' living room in frustration. "It doesn't make any sense!" he complained. "The surveillance footage from the coffee store shows Jenn still inside at the estimated time of the murder, but a witness places her at the scene at the same time. Either the witness is wrong or the time of death is wrong."

"Well, it is an estimate, after all," Stiles said soothingly as he placed a cup of coffee in front of Derek and sat down next to him on the couch. "The witness may not know the exact time they saw her, so there's a window of opportunity that the time frame falls into. That's why we need physical proof. The jails have been full over the years with people put away on the word of someone who ended up being wrong, whether it was malicious or not. It's the forensics that give us answers beyond a shadow of a doubt. Finding those skin cells under her nails was huge; she scratched her killer at some point during the attack." He paused thoughtfully. "She was beautiful and friendly, always a bit of a flirt. I wonder if she had a stalker or an admirer who took things too far."

Derek rolled his shoulders, trying to work out a kink. "Isaac and Scott have been checking up on her. She didn't have any known enemies, and even though she wasn't known to be in a relationship, a coworker mentioned that she'd been a bit secretive as of late and wasn't home much. They have Greenberg canvassing the area to see if anyone else saw anything and Boyd is investigating to see if there was maybe a secret lover."

"Every lead has to be explored," Stiles agreed. "In the meantime, though, you look like you're so tightly sprung you could snap at any minute." He raised up to maneuver himself behind Derek on the couch so that Derek sat between his spread thighs. Derek nearly whimpered out loud when he felt strong, capable hands begin to massage his neck and shoulders.

"I've missed you," Stiles whispered as he leaned forward to press a kiss to the nape of Derek's neck. The only reply Derek could manage was a low moan as Stiles worked at a large tension knot between his shoulders. It was equal parts pleasure and pain, and Derek was embarrassed to feel his cock stir in his jeans.

Stiles chuckled softly. "You are so delightfully responsive," he purred as he slid his hands around to Derek's stomach, working their way up under the dark colored Henley he wore. Derek felt his stomach tighten in involuntary response, and when he felt Stiles flick at his nipples with his thumbs, he hissed out a breath he hadn't realized he'd been holding.

"I think your left nipple is more sensitive than the right," Stiles observed as he pinched it teasingly, causing Derek to jerk in his arms. "Why do you suppose that is? Maybe because it's over your heart?"

"Stiles," Derek protested weakly, "I need to be working."

"You're working yourself too hard," declared Stiles, deftly opening Derek's jeans and cupping his cock before rubbing it through his briefs. "Don't mistake me; I want justice for Heather, but I don't want you killing yourself either."

Derek's eyes rolled back as pleasure traveled through him in waves. But he had been pushing himself for days now with very little rest, and Stiles' soothing shoulder and neck massage had relaxed him for the first time since this case started. Being held by Stiles was warm and comfortable, and Derek felt himself slipping away. He would be embarrassed later, but before he knew it, he was nodding off in Stiles' arms.

Stiles realized Derek wasn't responding to his touch and discovered the exhausted wolf had literally passed out in his embrace. He pressed an affectionate kiss to the area behind Derek's ear and smiled as Derek snuffled in his sleep. "My poor Sourwolf," Stiles murmured quietly so as not to wake him. "I know I'm asking a lot of you right now, but it's the only way we will find out the truth and capture Heather's murderer." He sighed sadly. "I have to admit, though, knowing you're doing it for Jennifer's sake makes it a bit of a hard pill to swallow." He stealthily slipped out from behind Derek, moving him so that he was laying on the couch with one of the pillows under his head. Tip-toeing to the hall closet, Stiles took out a spare blanket and returned to the living room to gently cover Derek up. He pressed a last soft kiss to Derek's cheek before seeking out his own bed.

The next morning Derek stood at Scott's desk, staring at him in disbelief. "Heather's family is demanding what?"

Scott looked harassed and irritable. "Her family thinks Heather's getting trashed in the media. They are pushing for us to arrest Jennifer and charge her with murder."

Derek shook his head in denial. "No, _no, _can't they see that if we arrest the wrong person things will only get worse?" He glared at Scott determinedly. "I just need a little more time, Scott. I swear I'll get the proof we need to find the real killer."

Scott huffed out a breath and nodded his head. "Fine. Start with this; Boyd found out that this guy was ticketed the night of the murder for illegal parking not far from where we found Heather. Seems he gave the officer giving the citation a hard time. Sounds like a real winner. Go check him out, see what you can find."

Derek read the paper Scott handed him. Ennis Fontaine, age 32. Alpha wolf. Ran his own successful business and had amassed a small fortune. Interestingly, though, it seemed he was no stranger to the police. Several complaints had been filed in the past, usually incidents like road rage and disturbing the peace, though nothing had ever stuck. As Derek skimmed the list of reports filed, one in particular caught his eye; a domestic violence complaint filed by none other than Kali!

This could be the break Derek was looking for. "I'm going to go have a chat with this Ennis character," he stated.

Scott nodded as he turned to his computer screen. "Take Isaac with you. Make it look like you're asking him for information, not accusing him. The last thing we want is for this dirt bag to lawyer up and make things more difficult."

Less than an hour later, Derek and Isaac sat in an office across town with Ennis Fontaine. He sat casually smoking a cigarette and had a smug, slick manner that set Derek on edge and made him want to rip the asshole's throat out with his teeth.

"And what time did you return to your car, Mr. Fontaine?" Isaac asked pleasantly, ignoring the tension in the room.

Ennis rolled his eyes and leaned forward angrily. "That's already on file with the department, Detective. I got ticketed by an idiot who is more worried about my being parked in front of a fire hydrant than he is a murderer being on the loose. I'm so glad to see my tax dollars at work," he sneered as he crushed the cigarette out in a nearby ashtray. "Now, if you're finished wasting my time, I'm a very busy man. My statement is on file and if you don't leave the premises immediately, I'm going to call my lawyer and sue the entire goddamn department for harassment!" As if to prove his point, he stood up and strode to his desk to pick up the phone.

While Ennis was distracted by his ill humor and agitation, Derek took a Kleenex out of his pocket and quickly picked up the discarded cigarette butt. He quickly tucked it in his jacket, careful to wrap it so it hopefully wouldn't be compromised before he could get it to Stiles. Isaac's sharp gaze let him know he hadn't missed anything, and he stood quickly once Derek was finished.

"I'm so sorry, Mr. Fontaine," Isaac said placatingly. "Of course we know you're busy. Everyone is concerned about this incident, and rightfully so. We're just trying to make sure that if there's anyone that can help us with information, we find it. Sometimes a potential witness is too frightened to come forward, or doesn't realize that even the smallest detail can be incredibly important. We'll take our leave now, but if you remember anything from that night, pease give us a call."

Ennis placed the phone back in its cradle, appearing mollified. "Of course. Such a terrible thing, what happened to that poor girl. Does the department have anyone they suspect?"

Derek gave him a cool, professional smile. "We are investigating all leads, Mr. Fontaine. We'll see ourselves out so we don't take up any more of your time." Giving him a terse nod, Derek and Isaac left and returned to the squad car they'd driven over.

"Such a charming guy," remarked Isaac sarcastically as they pulled out to return to the station.

"Definitely," agreed Derek. "He seems like he's hiding something. Did you notice that he didn't answer any of our questions? He either answered with a question himself or basically refused to answer. That's not suspicious at all," he huffed sarcastically with an eye roll.

"Good move, by the way, getting that cigarette butt," Isaac said admirably. "Stiles should be able to get DNA from that with no problem."

As soon as they got back to the station, Derek put the butt in an evidence bag and sealed it. To his disappointment, Scott decided to deliver it so he could check up on Stiles and see how he was coping. Derek could hardly fault Scott for his concern since he shared it, but he missed Stiles.

Later that afternoon, Stiles burst into their office. "Derek, you did it!" he shouted. "The saliva from the cigarette butt is a perfect match to the skin sample." He sobered quickly. "But there's something else. Testing of the skin determined there were actually cells from two individuals."

Derek wanted to hit his head on the desk. "Shit! Are we looking for a conspirator?"

"Well, not exactly," Stiles said as he began to explain. "Ennis just became the prime suspect, but at some point Heather scratched someone else as well and got their skin under her nails. We need to find that person in order to solve this case."

"Great! So we're back to square one!" Isaac groaned unhappily.

Stiles coughed uncomfortably. "Well, actually, I already found a match for the second skin sample as well. It matched a sample I already had on file." He looked around unhappily. "You won't like this."

Scott stared at Stiles, horrified realization dawning on his face. "No way. It can't be. Not Kali."

Stiles sighed heavily. "Go talk to her, Scotty. Find out what the hell is going on."

An hour later, Derek and Scott stood outside Kali's apartment. When she answered, her welcoming smile quickly faded to a look of wariness.

"Kali," Derek said gently, "We need to ask you a few questions. You know why we're here. If we are going to clear Jennifer, we need you to help us."

Kali let them in and showed them to a small, neat living room, seating them on the couch and offering coffee, which was politely refused. She sat on the love seat, nervously toying with the bandage on her arm.

"Where do I even start?" she asked shakily. "I'm sure you know by now that Ennis and I were once married. When we were dating, he was so charming and exciting. He liked to spend money on me, dress me up in sexy clothes and show me off. He'd take me to expensive clubs and restaurants, all in order to make others jealous of him. He dazzled me, completely swept me off my feet. But once we were married, I found out that he was jealous, possessive, and prone to anger and violence. He's also a cheating bastard that likes toying with other women to stroke his ego. I lost count of the number of times some idiotic girl came to me, threatening me if I didn't end things with him."

"Why put yourself through that? Why not get a divorce?" asked Derek.

Kali laughed bitterly. "He refused to give me a divorce. He likes having control over me, plus it gives him a nice little excuse to use when he's breaking things off with his other women."

"What about Jennifer?" Scott asked. "What does she have to do with all of this?"

Kali smiled sadly. "We were college roommates. She was my best friend, and when things got really bad, I called her and begged her to help me. She quit the police force and moved here to be with me. We became lovers shortly thereafter. It's the happiest I've been in years." She smiled mirthlessly, clenching her hands together in a tight ball in her lap. "I should have known Ennis would find a way to take that from me, too."

Scott leaned forward and touched her hands gently. "I need you to tell me exactly what happened that night, Kali."

Kali sighed and raised an hand to push a loose strand of hair back from her face. "Heather called me and asked me to meet her at the old bank. Strangely enough, she didn't want to demand I give Ennis a divorce; she was actually terrified of him. She worked for a company he did business with, and it seems he'd taken to stalking her. Sending flowers to her job, leaving notes on her car, getting her cell phone number somehow and calling all hours, day and night." She frowned. "I'm ashamed to say I told her I couldn't help her. When she suggested we go to the police together, I laughed and called her a stupid girl, which understandably upset her. She went into hysterics and came at me. I was able to subdue her, but she managed to scratch me along the way."

"Is that how you hurt your arm and face?" Derek asked curiously.

Kali looked at him flatly. "I'm an Alpha. Those piddly scratches were gone in no time. These," she gestured to her bandaged arm and cheek, "were courtesy of my darling husband, who decided I had interfered where he didn't want me."

"What happened next with Heather?" Scott asked.

Kali sighed unhappily. "I got the hell out of Dodge and advised her to do the same. Looking back on it, I wish I'd done more to help her. But I assure you, she was alive when I left her."

Derek looked her in the eyes. "Do you think Jennifer killed her?"

Kali flinched, but didn't look away. "No. Jennifer would never do that."

"Then I need you to give me every detail you remember of that day. Help us prove her innocence," Derek urged.

Kali took a shaky breath and nodded.

The next day, armed with a search warrant, Derek, Isaac and Scott all went to Ennis' opulent town house in the nouveau riche part of the city. When there was no answer to their knocks, Scott gave the order for the door to be broken down. There were no signs of life inside, but it looked like Ennis hadn't skipped town. Yet.

Scott took control from there. "Isaac, you and the crew search the house. See if you find any evidence that can be used in the case. Derek, come with me to Ennis' office. If he's there, we'll place him under arrest and take him in for questioning."

They sped to the office building, worried about losing any time and letting Ennis escape. They pulled into a parking lot for the building next door and carefully made their way over, guns loaded with wolfsbane bullets and ready for use if necessary. Scott peered around the corner of the front of the building to make sure the coast was clear and his eyes widened in shock. Derek ducked down to see for himself what had caught Scott's attention and felt his heart give a lurch. Parked in the main lot was a familiar blue Jeep.

"Aw, damn," Scott whispered. "I should have known Stiles would figure it out. I can't believe he was foolish enough to come by himself, but then again he's always managed to take care of himself. He isn't a Spark for nothing."

Even the reminder that Stiles had that kind of powerful magic at his disposal didn't make Derek feel any less agitated. "We have to get in there now. If Ennis has figured out the department is on to him, he's more likely to be desperate and do something rash."

Scott huffed out a breath. "You've got a point. Let's move, Detective."

They moved around and entered the office building. This late in the afternoon the other businesses that shared the space with Ennis' appeared to have closed for the day. Scott motioned for them to move forward, and as they approached the door, discovered it was frustratingly locked. Derek was ready to blast the doorknob off or kick the door in, but Scott surprised him by pulling out a credit card and jimmying it open.

Scott saw Derek staring at him in amazement and shrugged a shoulder. "My teen age years were interesting, to say the least, and my dad's an FBI agent. Long story for another time."

They quietly opened the door and closed it behind them. The office appeared deserted and was getting dark, but Derek noticed a light coming from the back area and motioned to it. Scott nodded, and they stealthily moved towards it. The light led them to a back storage area, where the door was cracked just enough for them to see inside. Derek's heartbeat picked up when he saw Stiles tied to a chair, staring defiantly at Ennis, who was rifling through his wallet.

"Let's see who you really are, _Miguel_," Ennis was saying. "Well, well, Dr. Stilinski. Who sent you to spy on me? Your father?"

"My dad doesn't know I'm here. Leave him out of this," Stiles spat. "You killed Heather, you bastard. And I'm gonna make sure you pay."

That caught Ennis' attention. "Was she your lover? Is that why she refused me?" he snarled. "I was good to that bitch and she wouldn't give me the time of day. Thought she was too good for me. She didn't think she was so much better than me when I snapped her pretty little neck," he taunted.

Derek caught Scott's eye. Scott nodded and retreated to the outer area where he could call for backup. They had a confession. Now they had to get Stiles out of there and take Ennis into custody.

Stiles' features had twisted furiously. "You're going to regret that," he promised, his voice dealt calm. "She was my friend, not a girlfriend, but I'll see you in hell for what you did to her."

Ennis walked around the chair cockily. "Seems I'm the one with the upper hand here, Dr. Stilinski," he mocked. "This pretty mouth of yours might be writing checks your ass will have to cash."

Derek fought back a snarl when Ennis reached out and ran his thumb over Stiles' lips before forcing it into his mouth.

"I don't fuck men, but then again you're pretty enough that I can forget you aren't a woman," Ennis remarked with an evil laugh. "It certainly won't be the first time I've plowed someone's ass. Will you scream and fight me? It makes it so much better when they do. I'll bet you beg so prettily, like the bitch you are."

Stiles spit in Ennis' face, causing him to draw back with an enraged growl. He shifted into beta form, pulling a knife out of his waistband. "You little shit!" he roared as he raised it in his fist. "Don't you know who you're messing with? I'm an Alpha!"

"So am I!" snarled Derek, shifting to beta form himself as he kicked the door open and darted forward to grab Ennis' upraised arm. He jerked him back and tossed him across the storage area into some shelves. Ennis leapt to his feet with a snarl, ready to fight.

"That'll be enough," Stiles said authoritatively, coming up next to Derek and blowing a fistful of purple powder into Ennis' face. He made a choking sound, clawing at his throat before gagging and falling weakly to his hands and knees.

"What the fuck was that?" Ennis wheezed. "And how did you get out of that chair? I tied those knots tight enough that you couldn't have possibly gotten out without cutting them. You didn't have a weapon, I checked."

"Oh, you mean the powder?" Stiles grinned maliciously. "That's just a special little wolfsbane mix I concocted. Won't kill you, it'll just make you wish it had once it really kicks in. It's gonna be awesome. As for getting free, well..." He shrugged out of his flannel, exposing his tattoos, which began to glow.

"You're a Spark? You've got to be fucking kidding me," groaned Ennis. He was starting to sweat, his body beginning to tremble as it was wracked by painful spasms.

Stiles smirked gleefully. "It's all true. I could have gotten out of those easily at any time, but I needed to keep you talking. These fine officers have you confessing not only to murder, but sounds like you're a low down, dirty rapist as well. I'll bet we can find victims who will be willing to come forward now that you're locked away."

Scott rejoined them. "I have the containment unit on its way," he said, watching Ennis writhe on the floor, black ichor dribbling from his mouth and nose. "Ugh, gross. Damn, Stiles, that is some nasty stuff. He's gonna think Eichen is a veritable paradise once that's run its course."

"I'm just sad he only inhaled it. I should have found a way for him to ingest it. It would have been even more painful," Stiles muttered darkly. He then turned and punched Scott in the shoulder, making him yelp in protest. "Took you long enough to get here. Do I have to do all the thinking for both of us?"

"I didn't know you'd be here until I saw your Jeep. Besides, I had to get the warrant first, Stiles," Scott said defensively. "I know you can't be bothered with proper procedure, but it's my job. You know the last thing we'd want is this guy going free because we went about things without following protocol." He rubbed his shoulder and frowned. "Damn, that actually hurt."

"Luckily, Detective Hale had my back," Stiles said as he gave Derek a warm smile.

Derek had been watching them silently, taking in the fact that apparently this sort of thing was perfectly normal for the two of them. Suddenly he felt unreasonably angry "You idiot!" he burst out, causing Stiles and Scott both to stare at him in shock. "Why would you come here alone like that? He could have hurt you, even _killed _you! What might have happened if we hadn't gotten here?"

Stiles regarded him with wide, surprised eyes. "I knew Scott would get here eventually with the Cavalry, Derek. And don't forget, I'm a Spark. If things had started getting too crazy I could have dealt with it, you just might have had a pile of ashes to deal with and not a perp. That would have involved a ton of extra paperwork, dealing with the press, and don't you agree it's better for Ennis to suffer in Eichen for a long time for his crimes, rather than the quick release of death?"

Derek flushed hotly in mortification. Deep down, of course, he knew Stiles could have handled things himself; he just also knew that the last time he'd been so afraid for someone had been when he had lost most of his family to Kate's irrational hatred. He didn't want to lose anyone else.

He didn't want to lose _Stiles. _The realization was staggering.

Derek jerked out of his mind numbing thoughts when Stiles touched his shoulder. "Are we okay, Sourwolf?" he asked tentatively.

Scott was watching them, his eyes knowing. "Why don't you two go inform Kali and Jennifer? I'll finish up here." He walked over to Ennis, who was still lying on the ground, groaning in agony. He slapped wolfsbane reinforced cuffs on him and began reading him his rights. "Ennis Fontaine, you're under arrest for the murder of Heather Gibson. You have the right to remain silent..."

Derek let Stiles lead him out to his Jeep. He was quiet as they drove to Kali's apartment. Unsurprisingly, Jennifer was there, and they all sat down in the living room to talk.

"We have Ennis in custody," Derek told them.

Kali released a pent up breath and slumped in relief, and Jennifer reached over and grasped her hand tightly.

"He has confessed to murdering Heather, and we think that's just the beginning of what we will be charging him with," Derek continued. "If you want to press charges for spousal abuse, come to the station. We're going to try to find other victims to come forward, so any help you can give is appreciated. We're going to put him away for a long, long time."

"It's over," Kali whispered brokenly, tears spilling down her cheeks. "I'm finally free. Thank you so much."

"There's something I would like to know," Stiles said, looking curiously at Jennifer. "How did your footprints and the coffee beans get to the crime scene? Why didn't you speak up?"

Jennifer sighed, squeezing Kali's hand tighter. "I knew Ennis had been after Heather and that Kali didn't want to be involved. I was trying to figure out a way to get him implicated somehow without getting the police directly involved since Heather was too frightened to go to them herself. She was afraid he would escalate and get more violent. The night of the murder I knew Heather had asked Kali to meet with her. I followed to try to see what was going on and saw Kali leaving the area, obviously very upset. I had a bad feeling about it, so I waited for her to get home and went to talk to her. When I saw her, Ennis had already hurt her and she wasn't healing. I tried asking about it, but Kali kept contradicting herself. When I went out to buy my coffee that night I went back to the old bank, since I knew that was where Heather had asked Kali to meet her."

"And you found the body," Stiles guessed.

"I did," confirmed Jennifer.

Derek was surprised by what he was hearing. "So you thought Kali killed Heather?"

Jennifer smiled sadly. "Yeah, I did. I thought Heather might have pushed her too hard and caused her to snap and lash out. That bastard had put Kali through so much hell, I couldn't bear for her to be be punished for his nefariousness. I couldn't just leave, so I scattered the coffee beans and deliberately left my footprints."

"You wanted us to suspect you instead?" Derek asked. "What if you'd been arrested and jailed for the crime?"

Jennifer shrugged, looking down. "I know it was dumb, especially since I'm an ex-cop, but I also knew the evidence was circumstantial and didn't prove my guilt. Even if I'd been arrested, a good lawyer would have gotten me off. And I would still have gone to jail gladly if it meant Kali was protected."

Stiles smiled at her. "It's because you love her. We're always protective of the ones we love."

Jennifer and Kali looked at each other, both smiling softly as they held hands.

"You've become quite a detective, Derek," Jennifer turned her smile to him.

"Thanks," Derek said. "You know, I always wanted to impress you when we were in school together. You were one of the top cadets, and I wanted to be the best cop I could be because of you."

Jennifer looked surprised. "I had no idea! Well, I'm very flattered to have been the inspiration for such a fine officer."

Derek smiled at her. He was happy that Jennifer had found love and was happy. "Do you ever miss it?" he asked curiously. "Do you miss being a cop?"

"On occasion," Jennifer admitted. "Usually on days where we have cranky customers who tip lousy, or when business is slow. But if it means being with Kali, then I can't really think of anything else I'd rather do."

* * *

><p>That night, Derek leaned his head back against Stiles' couch and sighed tiredly. "Case closed."<p>

"Congratulations, Detective," Stiles grinned. "Kudos on a job well done."

Derek raised his head to look at Stiles. "Thank you," he said sincerely. "We couldn't have done it without you. The forensics led the way, and you got Ennis to confess."

"Anything for you, Derek," Stiles said with a wistful smile. "Whatever it takes to make you happy. Even if you're in love with someone else."

"Who, Jennifer?" Derek asked, chagrined. "No, you've got it wrong. Anything I felt for her was nothing more than a crush. She reminded me of my first love, Paige." When he saw Stiles was listening intently, he continued. "Paige was my first girlfriend, and she was killed when she was bitten by a rogue omega. Her body rejected the bite and she didn't make it. She died in my arms. I was devastated and vulnerable, and that's partly why Kate Argent was able to get to me like she did. I know you know how that story went. I paid the ultimate price for it." He laughed bitterly. "I lost Paige and later lost my family. But anyway, Jennifer looked similar to how I imagined Paige would have looked if she'd lived. I think it reminded me of simpler times and I built up an image of her in my head that didn't exist."

Stiles shifted on the couch, moving a bit closer. "Then does that mean you're in love with someone else now?"

Derek huffed out a breath. "Yeah, I think I actually am," he said, realizing in that moment that it was the truth. "But it doesn't matter. I'm pretty sure it's one sided anyway."

"Really. What makes you say that?" Stiles looked intrigued. "Have you told whoever it is? Tell me! I wanna know!"

Derek scowled at him. "Why would I tell you? So you could laugh in my face?" he snapped. _Can't you figure out that it's you? How can someone so smart be so oblivious? _

"Awww, come on, Derek! I would _never _laugh at you. Just tell me, you'll feel better if you get it off your chest," Stiles coaxed, putting his arm around Derek's shoulders. "Who is it?"

Derek fought to ignore how good Stiles' touch felt. "What about you? Are you in love with someone?" he hedged._ Lydia?_

"Do you always answer a question with a question?" Stiles laughed. "All you're doing is making me more curious."

Derek felt himself giving in. It was disconcerting to realize he might be incapable of denying Stiles anything, even if it caused himself pain. "Fine!" he snapped, mentally preparing himself for humiliation. "It's _you,_ you idiot! I'm totally, madly, completely head over heels in love with you. There! Are you satisfied? Can I go home now to die of embarrassment in peace?"

"Oh, thank Christ," Stiles breathed out, moving to straddle Derek's lap and running his hands up into Derek's hair to hold him. "You have no idea how long I've been waiting to hear you say that. I was starting to think I was going to have to hold back forever."

Derek's head was spinning as he tried to process what Stiles was saying. "Holding back?" he asked weakly.

"I thought you were hung up on Jennifer. You seemed to like fooling around with me well enough, but I was sure that you were so invested in proving her innocent because of your feelings for her," Stiles explained.

"I was sure she didn't do it," Derek admitted, "but truthfully part of the reason I put so much into this case was because of how it affected you. I always want to solve the cases I work. But this was someone who had been important to you, and her death hurt you. I wanted to give you closure as much as I did her family."

"I don't think anyone's ever done anything like that for me before," Stiles breathed before pressing his lips to Derek's, kissing him fiercely.

Derek held to Stiles' hips, loving the feel and taste of him. But he still needed to know something: "And what about you, Dr. Stilinski? You have my confession, now you owe me one as well. Who are you in love with?" He waited with bated breath, heart pounding.

Stiles laughed delightedly. "Isn't it obvious? I'm completely and totally out of my mind in love with you. So much that I decided to go after a dangerously insane Alpha to help you prove the innocence of the person I had myself convinced you actually loved."

Derek's hold on Stiles tightened in remembrance. "God, Stiles, you have no idea how scared I was when I realized you were there with that bastard. I hated him touching you, and when he threatened to rape you I could have killed him without even the slightest remorse. I know your Spark would have overcome him, but don't ever scare me like that again. Please."

Stiles nuzzled into Derek's neck, rubbing his face against the skin and scenting him in the way that drove Derek crazy in the best way and made him grow hard sitting there on the couch. "I'll try my best, but only if you'll do the same. I know you're an officer of the law and there's times you'll have your life on the line. But you're my Sourwolf, too, and I need you to come home to me."

"Are you saying you need me to survive?" Derek asked, feeling giddy as Stiles slid down between his knees and began undoing his belt to open his pants.

"I'm saying we need to trust each other," Stiles said with a wink just before he lowered his head and swallowed Derek's cock down to the hilt.

Derek gave a soft grunt, resisting the urge to thrust up and fuck that perfect mouth. He tossed his head back with a low moan of pleasure, letting Stiles work him over with his talented mouth instead. It would be so easy to just let himself get lost to sensation, but his traitorous mind couldn't stop thinking about things.

"So why didn't you tell me earlier, how you felt?" Derek asked.

Stiles pulled off his dick with a soft pop and a chuckle, his lips dark pink and slick with spit. "Are you really going to interrogate me right now? I must be losing my touch or something. You shouldn't even be able to string two thoughts together right now."

"I'm serious!" protested Derek, shuddering as Stiles resumed sucking him off in earnest. "You just happen to be in the mood for confessions today? I was afraid you were only toying around with me and not serious at all. Half the time I was convinced you were messing with me and secretly pining for Lydia."

That brought Stiles to a halt. "Okay, first of all, don't ever talk about Lydia when your dick is in my mouth. So wrong, ew. And I already told you, Lydia and I are perfect for each other. As best friends. We love each other as brother and sister, and I would burn the world down for her if I had to. So would her fiancé, Agent Jordan Parrish from the FBI. I'm going to be a groomsman in their wedding and planned to ask you to be my plus one. Believe me, Lydia is no threat to you."

Well. Derek now felt a little foolish to have been worried, but the relief in knowing that he wasn't a substitute for someone else couldn't be denied. With that final perceived barrier between them now removed, Derek was ready for more. "Stiles, take me to bed." he said, feeling smugly pleased to have apparently caught Stiles off guard.

Stiles gaped at him for a moment, mouth open and apparently at a loss for words. Finally, his brain seemed to catch up. "Derek, are you sure? I've said all along that we would go at your pace. I don't want you thinking that's changed just because we managed to get our heads out of our asses. Not that I'd mind having anything to do with your ass. I'm actually very fond of your ass. In fact—"

"Stiles," Derek interrupted patiently, cutting off what was looking to become a ramble. "I don't want our first time having sex to be me bending you over this couch. There'll be time for that in the future, but if it's alright with you, I'd really like to make love in your bed."

Stiles jumped up and pulled Derek to his feet. "I fucking love you so much," he breathed, jumping up to wrap his legs around Derek's waist.

Derek carried Stiles effortlessly to his bedroom, depositing him with care onto the mattress and then shoving his own loosened pants and briefs off and kicking them to the side. His shirt quickly followed. Stiles was following his lead, pulling off his clothes and tossing them haphazardly off the bed. He lay back against the pillows, stroking his cock and watching Derek with bright eyes that seemed to have a bronze glow. The intricate tattoos stood out, and Derek promised himself that one day he would map every inch of them with his tongue, over and over until they were committed to his memory and etched in his brain.

"You've never let me touch you before," Derek remarked casually as he crawled onto the bed, sliding easily into predator mode.

"I wanted to," Stiles panted, reaching over to the nightstand to grab the bottle of lube. "I jerked off to you so much in the shower I was honestly worried about chafing. But I was also worried that you were letting me touch you like that all while pining for Jennifer."

Derek winced. "What was it you said about not talking about someone? Can we not mention Jennifer when I'm about to—"

"I know," interrupted Stiles apologetically. "You're right. It's just..." he faltered and looked away for a moment, heaving a deep breath. "You wouldn't have been the first straight guy who fooled around with me on the side in secret. I didn't want that, not from you."

Derek got it. It was actually rather comforting in a way that brash, exuberant Stiles was wracked by the same sort of insecurities that Derek had been. "Okay, let's just come to an understanding that neither of us was using the other. It's past now, right?" He used a finger to tip Stiles' chin up and looked into his eyes. "I love you, okay? And if you'll give me the chance, I'll show you every chance I get."

Stiles blinked rapidly and gave a shaky laugh. "Geez, Derek, I didn't realize what a romantic you were," he teased breathlessly.

"Luckily for you, you get the chance to find out all about me," Derek teased right back, nosing his way down Stiles' stomach. "I don't think I snore, but I tend to kick the covers off the bed. I don't like raisins and Brussels sprouts make me gag, but I could eat my weight in that Biscoff cookie spread. I want you to know me, and I want to know everything about you, but first off I want to get my first experience in giving head. So let's forgo the interview until after I suck your dick, and keep in mind that while I get the gist of things, I want you to tell me if I do it wrong."

"You want me to tell you if you suck at sucking?" Stiles chuckled, then gasped when Derek gave him a small nip on his hip in punishment.

Derek slid down a little further until he was laying between Stiles' spread legs and his cock was right in front of his face. He hadn't really planned how this moment would go, so now that he was here he was suddenly nervous. But then, how hard could it be, right? He was a guy. He had certainly received blow jobs before, none better than those Stiles gave him. He knew what he liked and what felt good to him. So he would start with that in mind and learn what Stiles liked along the way as well. It seemed like a win-win situation all around.

Leaning forward, Derek pressed a kiss to the tip of Stiles' cock before taking a quick swipe over the top with his tongue. He took a second to consider the slightly bitter taste before leaning in again to lick and kiss his way down the complete length. Stiles moaned softly and wiggled his hips, and Derek pinned him with his hands to hold him still. His grasp was firm, but not quite hard enough to bruise, and he couldn't help but wonder how Stiles felt about being marked by an Alpha. The idea of leaving physical proof of his possession made Derek feel positively primal.

Taking a deep breath, he bent down and took the head of Stiles' cock in his mouth, sucking gently.

"Oh, _fuck,_" breathed Stiles, squirming in Derek's hold.

Derek held on, determined to continue. His lips felt a bit stretched and the feel of Stiles' dick in his mouth was definitely different, but far from unpleasant. The skin was smooth and warm, just a bit salty. Derek gave an experimental swirl of his tongue around the head and was rewarded by another hissed swear by Stiles.

Feeling a little more confident, Derek relaxed his jaw a bit and attempted to take Stiles' cock a little deeper. He slid further down, running his tongue along the underside, moving down until he couldn't go any further without possibly gagging himself. Not sure he was quite ready to attempt deep throating, he instead dragged his mouth back up, making sure to add a little suction and tongue action when he reached the head again.

"God, you look incredible right now," Stiles said, sounding awed. He had raised up on his elbows and was watching Derek with bright eyes and flushed cheeks. "I wish you could see how amazing you look."

Derek figured if he looked half as good as Stiles did right now, he was doing pretty well. He took Stiles' cock in his mouth again and this time wrapped a hand around the base like Stiles had done to him that first time. Bobbing his head up and down slowly, Derek made sure to use his hand this time to add to the sensation he was creating. It seemed to be working, because Stiles dropped back on the pillows and groaned. He felt rather pleased with his first effort, and Derek looked forward to improving. Practice did make perfect, after all.

His own cock was so hard it hurt. Derek found himself thrusting against the mattress, desperately seeking friction. Every nerve in his body was alight and while he was enjoying having Stiles in his mouth, he wanted more. He wrapped his hand a little more tightly around Stiles and began jerking him off, using his spit to move easier.

"I want you," Derek growled, his voice more hoarse than usual, something that made him feel even more turned on. His senses were on overdrive and he was close to operating on pure instinct. He buried his face and the juncture of hip and thigh and breathed deeply. It suddenly struck him what he desperately needed right then.

"Stiles," Derek asked he raised his head. "Will you let me smell you? You always disguise your scent. I know it's different for you, but it's really important to me, and I really want you know what you smell like."

Stiles smiled beatifically at him. "All you had to do was ask."

Suddenly, Derek's senses were flooded with the most exquisite scent he'd ever smelled. It was like smelling fresh fallen rain in the woods on a spring day combined with the spicy sweetness of arousal and desire. As long as he lived, Derek knew he would never smell something so intoxicating. It was heady. Completely addictive. He wanted to immerse himself in it. He wanted to _drown_ in it for the rest of his life, and maybe for longer than that. He wanted to smell it forever and never stop. Once again, he felt his control slipping as the wolf prowled just under his skin, demanding release. Fighting a heroic battle to contain his primal urges, he continued jerking Stiles off, watching with fierce hunger as Stiles moaned and tossed his head. Finally, Derek watched with satisfaction as Stiles shuddered under him, white stripes of come splashing over his belly and Derek's hand. Without even thinking about it, Derek licked his fingers clean before leaning down and doing the same to Stiles.

"Jesus, Derek, that's so hot," groaned Stiles.

Derek prowled up Stiles' body, nipping and licking along the way, and kissed him fiercely and possessively. The taste of Stiles in his mouth was driving him wild, and Derek didn't just want, he _needed. _

"Stiles," he rasped, feeling the last vestiges of his control slip. No one had ever driven him to the brink like this, ever. Derek felt his claws pop out and his fangs drop. He lowered his head with a groan as his ears grew pointy and his face shifted. He knew his eyes were glowing bright red. Bitterly disappointed in himself, he moved to slide away from Stiles.

"Wait just a minute," protested Stiles, sounding confused. He stopped Derek by grabbing his shoulders. "What's wrong? I thought we were doing awesome, now you're trying to leave me?"

Derek felt shame flooding him and closed his eyes. "I'm sorry," he said, his voice thickened by his fangs. "I lost control."

Stiles took Derek's face in his hands. "Look at me," he demanded softly, waiting for Derek to do as he asked. When Derek finally opened his eyes, Stiles smiled at him. "I love you," he whispered. "I don't care that you're shifted right now. In fact, it's actually pretty hot. Look at me, finding out I have a fetish! Besides, it feels really good to know I made you like this."

Derek wanted to throw back his head and howl. No one had ever understood and accepted him like Stiles. Not even Paige, who hadn't known he was a wolf until she was dying in his arms. He shuddered as a wave of pure primal lust coursed through his body. If he didn't get inside Stiles soon, he was going to lose his mind. His claws presented a problem, but Derek knew just how he would solve it.

"Get yourself ready for me," Derek commanded, his voice low and throaty. "Let me watch what you do to open yourself up."

Stiles moaned softly. "Oh, god, I think I just discovered an exhibitionist kink, too." He reached down and picked up the lube he'd dropped earlier and squeezed a small amount onto his fingers, sliding them together to coat them thoroughly.

Derek watched with rapt attention as Stiles reached down and ran his slick fingers around his asshole, coating it with lube before he began pushing in with one finger. He worked it in and out of himself, twisting slightly before pulling out and adding a second finger. Stiles moaned as his body adjusted to the stretch and burn. Before Derek realized it, Stiles had added a third finger and was rocking his hips back and forth, fucking himself on his hand. He growled softly.

"I'm ready," Stiles gasped. "Come on, Derek, don't make me wait anymore. I've already waited for you so long." He pulled his fingers out of his ass and grasped Derek's cock, slicking it with the lube and making him shiver with need.

Derek could feel his heart hammering in his chest. He took Stiles' other hand in his own and held it to him, letting him feel the pounding under his palm. "Feel what you do to me?" he asked huskily.

"I do," Stiles answered breathlessly. "And if it's all the same to you, I'd like to feel something else as well."

"Okay," Derek said, nerves on fire with anticipation. He raised up to a kneeling position. "How do you want to do this? Do you want to get on your hands and knees?"

Stiles shook his head. "No, I don't think so. Not this time, anyway. I want to see you."

Derek nodded. He positioned himself between Stiles spread thighs, spreading his knees to support them. He leaned forward and propped himself up on one hand, using the other to hold his cock, dragging it up and down Stiles' asscrack before pressing it against his stretched entrance.

Stiles was looking at him in a way that made Derek feel like there wasn't anything in the world he couldn't do. He would have fought a pack of berserkers by himself if Stiles asked him to. He pushed in, gasping as he felt the tight muscle stretching to give him entry. Derek wanted to be gentle, but the wolf was demanding that he thrust and _take_. Struggling valiantly for control over his primal side, Derek moved slowly, bit by bit until he was sheathed entirely inside Stiles. It was the most incredible thing he'd ever felt. The tight heat surrounding his cock was beyond anything he'd experienced, and the pleasure was unreal. He supported his weight on both of his hands planted on the mattress, feeling them tremble slightly, though he wasn't sure if it was from exertion or excitement.

"I need you to move," Stiles urged, tightening his thighs around Derek's waist and further driving him out of his mind.

Derek exhaled loudly and withdrew about half way before thrusting in again. The tight, hot drag around his cock nearly had his eyes rolling back in his head, and he pulled back and thrust again. Finally, he got a rhythm going, the push and pull that buried his cock over and over in Stiles' perfect ass the closest thing to heaven he'd ever experienced. He shifted on his knees to change the angle of his thrusts and knew he'd hit pay dirt when Stiles tossed his head back with a loud moan. His fingers tightened on Derek's shoulders, gripping hard enough that were he not a werewolf, he'd surely have bruises. He snarled in satisfaction.

"Oh, fuck, Derek, so deep. Yeah, right there, do that again," Stiles managed to say as he began moving his own hips, meeting each of Derek's thrusts with his own.

Derek felt possessive pride sweeping through him, his wolf preening at satisfying his mate. Stiles was getting hard again, and Derek shifted slightly to lick his own hand before wrapping it around Stiles and stroking him. He felt clumsy, trying to stroke and thrust at the same time, but it seemed to be working because Stiles moaned loudly again, thrashing his head back and forth on the pillow. Sweat beaded up on his forehead, and the skin that wasn't covered with tattoos was flushed. His lips were bitten a tantalizing pink and his pupils were blown wide.

He was the most beautiful thing Derek had ever seen.

Derek kept moving, trying to angle his thrusts just right and driving Stiles to the edge. He felt amazing under him, the way his lithe form responded, muscles moving with each roll and thrust of his hips. Stiles licked his lips and Derek was entranced all over again as he followed the movement with his own tongue.

"I'm getting close," Stiles whimpered in between smacking kisses.

"It's okay, I've got you," Derek said, increasing his movements and closing his eyes. He allowed himself to get lost to sensation, each drag of Stiles' ass around him twisting the hot lust inside his gut tighter. Just when he wasn't sure if he could hold off any longer, Stiles jerked under him, crying out loudly. His ass clenched tightly around Derek's cock as he came over his own stomach, the tightness all Derek needed to punch him right over the edge. He tossed back his head and howled as he came, his claws ripping through the sheets and the mattress. He collapsed on top of Stiles, trying to remember exactly how to breathe. His cock still pulsed and Stiles randomly tightened around him as they both worked through their climax.

It might have been two minutes, or maybe it was two hours. Derek finally realized he was still laying on top of Stiles, and Stiles was slowly running his fingers up and down his back.

"God, I'm sorry. I must be heavy by now," Derek apologized as he leaned up.

Stiles smiled softly at him. "You're heavy as a horse, actually. But I don't mind. I like having you."

Derek huffed a short laugh. He had shifted back to human form without even knowing it, and his body felt like he'd had the most amazing workout of his life. He nuzzled at Stiles' neck, scenting him before kissing him. "I like being here. But we need to clean ourselves up or else were going to be gross pretty quickly. And, uh, I may owe you a new mattress now. I might have clawed holes in this one."

Stiles stretched, wincing slightly then humming in satisfaction. "Can't be helped. Maybe we'll save this one for when we want hot, crazy, wolfy sex."

"You're awful," Derek said, rolling his eyes.

Stiles gave him a shit eating grin. "Yeah, I am. But you love me."

Derek's eyes softened. "Damn straight I do."

* * *

><p>The next day at work Scott burst into the office. "Isaac! Derek! We've got word of an incubus, three victims from just last night alone. Let's roll!"<p>

Derek and Isaac both jumped up, eager to get on the case. As they rushed down the hall, they ran into Stiles, labcoat covering his tattoos and sucker in his mouth.

"On your way early this morning, I see!" Stiles said cheerily. His smile softened when he caught Derek's eye, and Derek felt his heart leap the way it always did for Stiles.

"Yep! Got an incubus on the loose, expect the lab to be busy soon!" Scott said excitedly, obviously eager to be going.

Stiles nodded. "I'll be waiting for you," he said, giving Derek a meaningful wink. Derek grinned at him as he followed Scott and Isaac out the door.

* * *

><p><strong>END<strong>

**ittlebitz . tumblr . com**


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